Occasionally, Mailbird may display an error message stating [AUTHENTICATIONFAILED] Invalid Credentials (failure), as shown in the image below:

This error message will generally appear when you are connecting an email account to Mailbird for the first time, or if you recently changed the password for an email account which is already connected to Mailbird.

This is a very simple problem to fix, and although this error message is being shown to you by Mailbird, in reality it is originating from your email provider's own server, where you account is hosted. Mailbird is simply acting as the messenger.

If you come across it, please make sure that the username and password provided are correct, because this error is triggered whenever part of your credentials are incorrect.

If you would like more information or guidance regarding this issue, then you may also wish to refer to our Knowledge Base article here which goes into more detail about this specific problem.