Why Is My Email Not Working? An Email Troubleshooting Guide

When your email stops working, the fastest way back to a working inbox is not to change settings at random but to narrow the problem down until only one cause is left. This guide is that method: a plain-language decision tree for the email faults people hit most often on a Noiz mailbox, whether you send and receive through a desktop program such as Outlook or Thunderbird, a phone, or Noiz webmail. It is written for anyone with a mailbox on a Noiz hosting plan (a mailbox is also called an email account), and it is the hub that the more specific Noiz email guides branch off from.

Work through it in order. Start with the settings reference and the single sign-in test in the next two sections, because that test alone tells you whether the fault is on your device or with the mailbox itself, and that answer decides everything that follows. Then jump to the section that matches your symptom: cannot send, cannot receive, password rejected, connection timing out, mail going to spam, mailbox full, or it worked yesterday and not today.

Last reviewed: 27 July 2026, against Plesk Obsidian 18.0 (latest stable) and the Roundcube webmail it ships. This guide is written for Noiz hosting and is kept current against Plesk. It complements, and does not replace, the official Plesk documentation linked below. Panel labels and app screens shift slightly between updates, so where a screen differs from the wording here, the setting names, ports and values still apply.

Official Documentation Reference

• Plesk Obsidian Customer's Guide: the official reference for managing your mailbox, forwarding, autoresponders and spam filtering from the Plesk panel that Noiz runs.
• Outlook help and learning (Microsoft): Microsoft's own troubleshooting for the Outlook desktop and mobile apps, useful for app-side faults this guide traces to your client.
• RFC 8314: TLS for Email Submission and Access: the internet standard behind the encrypted ports Noiz uses (465 for sending, 993 for IMAP, 995 for POP), and why the old unencrypted ports are obsolete.

Prerequisites

• A mailbox that already exists on your Noiz plan. If you have not created it yet, do that first: see How to create an email address in Plesk. Nothing below can connect to a mailbox that has not been set up.
• The full email address and its current password. The username for Noiz mail is always the whole address, for example [email protected], never just the part before the @.
• Access to whichever app or device is failing, so you can check its settings, and if possible a second way in (webmail, or a phone on mobile data) to compare against.

Know Your Noiz Mail Settings

Almost every email fault comes down to one of these values being wrong somewhere. Keep this table in front of you while you troubleshoot. Wherever you see yourdomain.com, replace it with your own domain: it is an example placeholder, not a real server.

If you use POP instead of IMAP, the only change is the incoming port: 995 with SSL/TLS on the same hostname. The outgoing settings never change. Two rules catch most people out:

• The username is the whole address. A username of just you will fail to authenticate every time.
• Noiz mail is encrypted throughout. Use the SSL/TLS ports (993, 465, 995) only. The old cleartext ports (143, 110, 25, and 587 without TLS) are not used, and pointing an app at them is a common reason sending or receiving silently fails.

Start Here: The One Test That Halves the Problem

Before changing a single setting, sign in to Noiz webmail. Noiz webmail talks to your mailbox directly on the server, using none of your device's app settings or your local network's mail path, so it is the cleanest possible test of whether the mailbox itself is healthy. See How to access email from Plesk webmail for the sign-in address, then read the result:

• Webmail signs in and mail sends and receives normally. Your mailbox, password and the Noiz mail server are all fine. The fault is on the device or app you were using, or on the network it was connected to. Head to the symptom section below and focus on that device's settings, not the mailbox.
• Webmail rejects your password, or you cannot get in at all. The fault is with the account or the server, and no amount of changing settings inside Outlook or your phone will fix it. The likely causes are a wrong or changed password, a full mailbox, or a suspended service. Go straight to the password, mailbox-full, or suddenly-stopped sections.

This one test tells you which half of the problem to work on, and it stops the most common mistake in email troubleshooting: rebuilding an app account over and over when the real issue is on the server, or resetting a healthy password when the real issue is one app setting.

You Cannot Send Mail (but Receiving Works)

When mail arrives but will not leave, the problem is nearly always the outgoing (SMTP) side. Check these in order.

• Outgoing port and security. The SMTP server must be mail.yourdomain.com on port 465 with SSL/TLS. An app set to port 587, 25, or "no encryption" is the single most common cause. Correct it to 465 and SSL/TLS.
• Outgoing authentication is switched off. Many apps have a separate tick box such as "My outgoing server requires authentication" or "Use username and password". Noiz requires it. If it is off, or set to "same as incoming" but the incoming login itself is wrong, sending is refused. Turn authentication on and enter your full email address and password.
• The username is not the full address. The outgoing username must also be [email protected] in full. Apps often leave the outgoing username blank or shortened even when incoming works.
• Your network is blocking the mail port. Some office, school, hotel and public Wi-Fi networks, and a few home routers, block outbound mail ports to curb spam. The tell-tale sign is that sending fails only on one network. Test by sending from the same app over mobile data or a different connection; if it works there, the block is the network, not your mailbox.
• Security software in the way. A local antivirus or firewall that scans email, or a VPN, can intercept the outgoing connection. Temporarily disable email scanning or the VPN to test, then re-enable it and add an exception if that was the cause.

If you are unsure your app is configured correctly, re-check it against the Noiz settings using the guide for your program: Thunderbird or iPhone and iPad. Microsoft's Outlook help covers the equivalent screens in Outlook.

You Cannot Receive Mail (but Sending Works)

If you can send but nothing new arrives, work down this list before assuming mail is lost.

• Check the Junk or Spam folder first. Filtered mail is not missing mail. Look in Junk both in your app and in webmail, since a message flagged on the server may never reach your app's inbox.
• Confirm the incoming settings. Incoming should be mail.yourdomain.com, port 993 (IMAP) or 995 (POP), SSL/TLS, full-address username. A POP account set to "remove from server after download" on one device will pull mail down so your other devices and webmail never see it.
• Is the mailbox full? A mailbox at its size limit stops accepting new mail and the sender gets a quota bounce. See the mailbox-full section below.
• A filter or forwarder is diverting mail. A rule set up earlier, or a forwarding address, can move or redirect incoming messages before you see them. Review any mail rules and forwarders on the mailbox.
• Ask the sender to check for a bounce. If one specific person's mail never arrives, ask them whether they received an automated failure notice. The wording of that bounce (unknown user, mailbox full, message rejected) names the exact cause and is worth quoting to Noiz support.
• Recently moved the domain to Noiz? If your domain's mail was only just pointed to Noiz, allow DNS time to take effect. Until it does, incoming mail can still be delivered to the old host.

Your Password Is Rejected, or You Are Asked for It Again and Again

A password that keeps being refused, or a login box that reappears every few minutes, usually means one of the following.

• The username is not the full email address. This causes more "wrong password" errors than an actually wrong password. Set the username to [email protected] in full, for both incoming and outgoing.
• The password really is wrong, or was changed. Confirm it by signing in to webmail (the test above). If webmail also refuses it, the password is the problem: reset it in the Plesk panel where the mailbox lives, after you log in to Plesk, then update every device with the new password. A single device still holding the old password can trigger repeated prompts and, on some servers, temporary lockouts that affect your other devices too.
• An older app is negotiating an outdated login method. Some long-standing desktop clients try an obsolete authentication mechanism and fail even with the correct password. In the account's security settings, set the authentication method to normal or plain password over SSL/TLS (not "encrypted password", "secure password authentication" or a challenge-response option). The encryption comes from the SSL/TLS connection, so a plain-password login is both correct and safe here.
• A typo you cannot see. A trailing space, a swapped character, or Caps Lock will all read as a wrong password. Re-type it rather than relying on a saved value, and re-tick "remember password" once it works.

The Connection Times Out or the Server Cannot Be Found

If your app hangs, reports a timeout, or says it cannot find the server, the issue is reaching the mail server rather than logging in to it.

• The hostname is misspelled. It must be exactly mail.yourdomain.com with your own domain, no extra spaces. A "server not found" error often traces to a single wrong character.
• Your network is blocking the mail ports. As with sending, some networks block the mail ports outright, which shows as a timeout on both incoming and outgoing. Test the same account over mobile data or another connection; success there points at the original network.
• DNS has not caught up. If the domain recently moved to Noiz, mail.yourdomain.com may not yet resolve everywhere. This clears as DNS takes effect. Webmail is a useful check in the meantime, as it does not depend on your device resolving the mail hostname.
• A VPN, proxy or security suite is intercepting the connection. Turn these off briefly to test. If the connection then succeeds, add an exception for your mail app rather than leaving the protection off.

Your Mail Is Landing in Spam

There are two very different versions of this, and the fix depends on the direction.

• Mail you send is landing in other people's spam or junk. This is a deliverability matter, decided by your domain's sending reputation and its authentication records (SPF, DKIM and DMARC), not by any setting in your app. Ask a recipient to mark one of your messages as "not spam" and to add your address to their contacts, which helps immediately. For the underlying records, deliverability is configured at the domain level on Noiz hosting; if outgoing mail is consistently filtered, raise it with Noiz support so the domain's authentication can be reviewed.
• Legitimate mail you receive is going to your own Junk folder. Mark the message as "not spam" and add the sender to your contacts or safe list. Doing this in webmail as well as in your app teaches the filter on the server, not just on one device.
• You are receiving a flood of spam, or your address seems to be sending spam. That is a different problem with its own guide. See How to determine the source of spam and reduce it, which covers finding where unwanted mail is coming from and cutting it down.

Your Mailbox Is Full

Every mailbox has a size limit. When it is reached, new mail stops arriving, senders receive a "mailbox full" or "over quota" bounce, and some apps also refuse to send because they cannot save a copy to the Sent folder. The mailbox is not broken; it simply has no room.

To free space, sign in to Noiz webmail or your IMAP app and:

• Delete large, old messages, sorting by size to find the biggest first. Messages with attachments are usually the heaviest.
• Empty the Trash or Deleted folder and the Junk folder afterwards. On most setups, mail sitting in Trash still counts towards the limit until it is purged.
• Remember to clear the Sent folder too; years of sent attachments add up.

You can see how much space a mailbox is using, and its limit, in the mail settings for that address after you log in to Plesk. If you genuinely need more room than the current limit allows, contact Noiz support to have the mailbox quota raised on your plan.

It Was Working, Then Suddenly Stopped

When email worked fine and then stopped without you touching it, something changed. Finding the change is faster than checking every setting, so ask what is new since it last worked.

• A password was changed on one device but not the others. If you or a colleague reset the mailbox password, every device needs the new one. The devices still holding the old password will fail and can cause repeated prompts across all of them. Update them all, or see the password section above.
• Mail security was tightened. When a mail platform moves to encryption-only connections, older apps still set to a cleartext port or an outdated login method stop working overnight, even though nothing looked wrong before. The fix is to bring the app in line with the Noiz settings: SSL/TLS on ports 993 and 465, normal password, and the full email address as the username.
• The domain or its DNS changed. Moving nameservers, changing MX records, or transferring the domain can interrupt mail until the change takes effect. If the domain was recently touched, that is the first thing to reconcile.
• An app updated itself. A phone or desktop update can reset an account's ports or security back to a default that does not match Noiz. Re-check the settings against the table above.
• The mailbox filled up. Mail that "just stopped arriving" is often a mailbox that quietly reached its limit. Check the mailbox-full section.

Once you have identified the change, the fix is usually to undo it or to reconcile the app to the current Noiz settings. Re-running your client's setup guide (Thunderbird, iPhone and iPad) from scratch is often quicker than hunting for the one changed field.

When to Contact Noiz Support

If you have run the webmail test and worked through the matching section and email still will not behave, open a support ticket. The team can resolve it far faster when the ticket includes:

• The full email address affected.
• Whether the problem is sending, receiving, or both.
• Whether Noiz webmail works for that mailbox (the single most useful thing to state, from the test above).
• The app and device, for example Outlook on Windows 11, or Mail on an iPhone.
• The exact error message, copied word for word or as a screenshot.
• When it last worked and what changed around then, if anything.
• Whether it fails on every network or only one.

On Noiz managed plans the support team can check the mailbox, its quota and the mail server from the inside and tell you the precise value to correct, which is usually the quickest route once the on-device checks above are done.