Isolate the problem
- Record the exact error and when it started. Does it affect one recipient, one device or every outgoing message?
- Try sending a short message through your account’s webmail. If webmail works, focus on the email app’s outgoing settings.
- Check that the mailbox and hosting service are active, and review storage usage.
Use the webmail link and mailbox details supplied for your account. Do not assume that another customer’s server settings apply to yours.
Check the email app
Compare its outgoing server, username, authentication method, port and encryption mode with your supplied settings. Incoming mail working does not prove the SMTP settings are correct.
If a password recently changed, update the saved credentials on every device. Do not disable certificate checks or accept a certificate mismatch as a workaround. Avoid repeated retries if the server rejects authentication.
Send useful details
Open a customer support ticket with the affected mailbox, app and device versions, exact error and whether webmail can send. Mask passwords and unrelated personal information in screenshots. If only one destination fails, include the rejection text privately in the ticket.
For domain changes, review DNS records before changing mail routing. We can help with business email setup and migration.
Further reference: Mozilla’s outgoing email troubleshooting guide.