Why Some Email Apps Stop Working After a Mail Security Upgrade

From time to time you may notice that an email program which previously worked suddenly starts reporting connection errors or refusing to log in. This is frustrating, but it is rarely a server fault. In most cases the problem is outdated or unsupported software on your device that can no longer meet modern security requirements. This guide explains what changed, why some older apps stop connecting, and exactly what you need to do to get email working again.

Last reviewed: 27 July 2026. This guide reflects the current Noiz mail security requirements (encrypted connections using TLS 1.2 or higher, authenticated submission only) and is kept current as email clients and operating systems reach end of support. It complements, and does not replace, the vendor documentation linked below.

Official Documentation Reference

• Microsoft: Windows 10 end of support
• Microsoft Lifecycle: Outlook 2016 support dates
• Mozilla Thunderbird: system requirements

What changed on the server side

Noiz has tightened mail security controls to keep the platform aligned with PCI DSS and South Africa's POPIA requirements. In particular:

• Plain-text authentication and unauthenticated relaying over port 25 have been disabled. Port 25 is now used only for server-to-server delivery, not for sending mail from your own apps.
• Only encrypted connections are accepted for IMAP, POP3 and SMTP, and the connection must negotiate TLS 1.2 or higher. The older TLS 1.0 and 1.1 protocols, and the long-obsolete SSL protocols, are refused.
• Mail services are aligned with current secure mail authentication practice and regulatory compliance.

These changes keep your mailboxes secure and compliant. The side effect is that older software which only speaks insecure protocols can no longer connect. This is deliberate, and re-enabling the old protocols is not an option.

Why older email apps stop working

An email client has to support modern encryption to connect to a secure server. Apps and operating systems that no longer receive updates are stuck with outdated cryptography, so they fail the moment the server insists on TLS 1.2 or higher. Common culprits:

• Windows 10: Microsoft ended mainstream support for Windows 10 on 14 October 2025. It no longer receives free security updates, and its built-in mail components will fall further behind modern security standards over time. Windows 7 and 8.1 are even further out of date and will not connect at all.
• Outlook 2013 and 2016: These editions were released long before today's security expectations and are no longer fully supported. They frequently fail to negotiate TLS 1.2 correctly, which shows up as repeated password prompts or a flat connection failure even when the password is correct.
• Old phones and tablets: The stock mail app on an ageing Android or iOS device can hit the same wall. If a phone can no longer install operating-system updates, its mail app may not support the required encryption.
• Thunderbird as a reliable alternative: On a supported operating system, Mozilla Thunderbird is a strong choice. It is free, open source, actively maintained, and fully supports modern security protocols.

How to confirm the server is not at fault

Before spending time troubleshooting a device, it helps to know the server side is healthy. The Noiz mail servers are kept up to date and compliant:

• All mail traffic must use TLS 1.2 or higher; no insecure plain-text logins are permitted.
• Certificates are issued by Let's Encrypt and pass standard verification checks.
• Current, well-maintained clients connect to the same mailbox without any special configuration.

The practical test is simple: if a modern client (for example Thunderbird on an up-to-date computer, or the mail app on a current phone) can log in to the same account, the mailbox and server are fine and the fault is the older software.

The correct secure settings to use

When you set up or repair an account, use encrypted settings throughout. These are the standard secure values for Noiz mailboxes:

• Incoming, IMAP: port 993, connection security SSL/TLS.
• Incoming, POP3: port 995, connection security SSL/TLS.
• Outgoing, SMTP: port 465 with SSL/TLS, or port 587 with STARTTLS. Do not use port 25 for sending from your app.
• Authentication: required for outgoing mail, using your full email address as the username and your normal password. The password travels inside the encrypted connection, so "normal password" is the correct setting to choose.

Replace the incoming and outgoing server names with the mail host shown in your Noiz control panel for the mailbox (this is usually mail.yourdomain.com, where yourdomain.com is your own domain).

What you need to do

To keep using your email securely:

• Make sure your operating system is still supported and fully updated: Windows 11, macOS with current updates, or a maintained Linux distribution. If you are still on Windows 10 or older, plan an upgrade.
• Upgrade your email client to a supported version. Thunderbird is recommended where you are free to choose.
• If you use Outlook, run a currently supported edition (Microsoft 365, or Outlook 2021 or later) and install its updates.
• Remove and re-add the account using the encrypted settings above if it still fails after updating. A stale profile can hold on to old, insecure settings.

Troubleshooting

• Symptom: repeated password prompts even though the password is correct. The client is failing the TLS negotiation, not the login. Confirm the ports and connection security match the secure settings above, and update or replace the client.
• Symptom: "cannot connect to the server" or "the connection to the server failed". Usually an outdated client that cannot negotiate TLS 1.2. Test the same account in a modern client to confirm, then update the failing software.
• Symptom: mail receives but will not send. The outgoing server is still set to port 25 or has no authentication. Switch to port 465 (SSL/TLS) or 587 (STARTTLS) with authentication enabled.
• Symptom: an Outlook error such as 0x800CCC1A referencing SSL. The Outlook edition cannot complete a modern secure handshake. Update Outlook or move to a supported client.

Summary

Security cannot be relaxed by re-enabling outdated protocols; these controls protect both your data and the Noiz infrastructure. If an email app has stopped working after the mail security upgrade, it is almost always because that app or the device it runs on no longer meets today's encryption requirements. The fix is to update the software, correct the account to encrypted settings, or move to a supported client such as Thunderbird.

If you have updated your software and applied the secure settings above and email still will not connect, the Noiz support team can check the account and confirm the server side from their end. Open a ticket from your client area with the exact error message, the app and version you are using, and the operating system on the device.