Troubleshooting

Guides to help diagnose and fix common email issues, including connection errors, authentication problems, and client configuration.

Outlook IMAP login fails with correct password due to DIGEST-MD5 on Plesk mail server

Summary Some Outlook (Office 2021/2024 LTS) clients fail to log in via IMAP even when the...

Why Outlook mailboxes over 50 GB may cause corruption issues

When using Microsoft Outlook, very large mailboxes can cause performance issues and even file...

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...

Winmail.dat attachments: cause, impact, and fixes (Microsoft TNEF)

Summary: If your recipients see a single winmail.dat file instead of normal attachments, the...