Cannot Send/Receive -Server said Authentification Failed

Starting 2 days ago, EM Client started asking for username/password at startup and when I tried to send/rec. I just hit enter as the info was already there. Today I got home and the info that is there will not authenticate. I’ve tried to manually enter it, and also to change my password on the account settings. Next I tried to change the POP3 and SMTP credential authentification settings with no luck. Tried the diagnostic fix for both POP and SMTP and it failed. Finally tried to start a new identical account and that hasn’t helped.

could us your POP3 and SMTP logs? Go to menu Tools->Settings->Logging and check “POP3” and “SMTP”. Then restart eM Client, try to simulate the issue and send us (with reference to this topic) the logs using the same logging settings window.