Can receive but can't send email using gmail account

[AC Question]

I have 3 gmail accounts and can send from 2 of them. The 3rd has suddenly stopped sending. The error that the other server returned was: 334 VXNlcm5hbWU6 334 UGFzc3dvcmQ6 535 5.7.0 authentication failed (SMTP AUTH failed with the remote server). I can also send through Yahoo! and Hotmail accounts.

I still can receive emails, just can't send from my phone. Galaxy 5s.

Chris

 

[nedenlinger]

Sometime this can happen if you linked an external email to your GMAIL, when you had set up an alias as default sometimes ago, this maybe expired or no longer in service.
An alias Being out of service can cause the problem of sending msgs failure.
check if you are using it by looking on dropdown below destination input area

 

[Delta Hodge]

This happened to me sometime ago. What I did to get going again is delete the email that's giving problems and add it back and it worked fine for me.