Connection fails
An account will not connect, during setup or suddenly after months. The good news: the causes are almost always the same four, and they can be ruled out one by one.
YouniqMail shows where things go wrong in several places: as a red warning triangle next to the account in the sidebar (the tooltip names the reason), as a notice in the header and as a message when sign-in fails.
1. Is it the network?
Section titled “1. Is it the network?”Sounds banal, saves half the search: do other accounts work? Does the browser load pages? Hotel and corporate networks like to block the mail ports (993, 465, 587) while the web works. YouniqMail then shows Offline because it cannot reach its mail servers. Only a different network helps here, or a word with IT.
2. Password and sign-in method
Section titled “2. Password and sign-in method”The most common case behind “sign-in failed”:
- App password needed? iCloud, Yahoo and Gmail require one, many others do as soon as two-factor sign-in is active. The regular password is then always rejected.
- IMAP enabled? GMX and WEB.DE deliver only after enabling it in their webmail.
- Password changed? After every password change at the provider, the new one has to reach the account too: Settings → Email Accounts, Change IMAP/SMTP Settings on the account, enter the new password (fields left empty keep the stored one) and check with Test Connection. Accounts with a Microsoft sign-in do not have this route: remove the account and add it again, see Microsoft.
After a sign-in error, syncing of the account pauses. New mail only arrives again once the credentials are right.
3. Server details
Section titled “3. Server details”For manually configured accounts, a character-by-character comparison with the provider’s documentation pays off, see Setting up any provider:
| Field | Typical mistakes |
|---|---|
| Server | mail. instead of imap., typos in the domain |
| Port | 993 for IMAP (143 with STARTTLS); 465 with SSL/TLS or 587 with STARTTLS for SMTP |
| Encryption | SSL/TLS and STARTTLS swapped |
| Username | full address instead of short name (or vice versa) |
If you change the encryption, YouniqMail sets the usual port along with it; if a port does not match the encryption, the form warns you.
Incoming and outgoing are separate construction sites: Test Connection checks IMAP first, then SMTP, and tells you which part fails. If mail arrives but does not go out, the SMTP side is at fault.
4. The provider itself
Section titled “4. The provider itself”Outages happen. The provider’s status page (or a quick search for “provider outage”) settles in seconds whether a thousand others have the same problem right now.
Special cases
Section titled “Special cases”Proton Mail: Connection errors almost always mean the Bridge is not running. After a reinstall, the Bridge may also show a new certificate; you confirm it in the account settings.
Antivirus and firewall: Some security products insert themselves into mail connections (“SSL scanning”) and replace the server’s certificate in the process. YouniqMail rejects such connections; the certificate check cannot be turned off. An exception for YouniqMail in the security product solves this.
Proxy: There are no proxy settings of their own for mail connections; YouniqMail needs direct access to the mail ports.
Worked for months, then stopped, with no change: Usually a revoked app password, a withdrawn sign-in, or a server-side migration. The tooltip on the warning triangle in the sidebar names the reason; the logs provide the long version.