I all the sudden started getting an unauthorized error message popping up and wanting me to enter my password. I’ve been using em Client for several months now and this just started happening. I do not recall entering a password when signing up, but did find this info in the account settings. Since this just showed ***, I am not usre what might have been there. I replaced what was there with my Yahoo (email I am accessing) login credentials, but the error is still coming up.
PLEASE HELP! 
The same thing happened to me today. Did you get any help resolving the issue?
I have not. Very frustrating!
Hello Glen,
Could you please try removing the account and configuring it again (Menu > Tools > Accounts) if it is set as IMAP? This might simply solve the auth issue.
Regards,
Russel
Russel - any way to figure out which account these pops up refer to. I have 10 different email and calendar accounts and get the same thing. The problem is 3 of the email logins and 2 calendar/contacts use the same email address for the login so I have no idea which of the 5 is generating the error. And even though I get the pop up - I am still getting emails to the 3 accounts that use the email address in the pop up.
Hello Teo,
This seems as a minor authentication issue so I believe you are still getting emails and calendar data despite the error window. In past, this was related to Google OAuth or Jabber/XMPP so please check these accounts.
Regards,
Russel
I did this and still getting promted
I am having the same problem and I only have one account. Just today I started getting authentication error messages. I have re-entered the email address and password in the Account General and SMTP pages and tried both the “use Identity credentials” (whatever the hell that is) and “use these credentials” but nothing helps. I am hesitant to delete the account and recreate it as I have imported a lot of e-mails from windows live mail and from pst files and I am not sure whether I will lose them. Very frustrating!!!
Hello John,
If you have problems with Yahoo mail, go to Yahoo Webmail > account security and check that “Two-step verification” is OFF.
Regards,
Russel
Hello Glen,
I am sorry for the late reply but did you try switching off the setting: “Two-step verification” in Yahoo webmail Account security?
Regards,
Russel
No, but why would I want to use something less secure?
Don’t be fooled thinking that two-step verification is more secure than an encrypted password - it is not. Unless you are using something like a USB security key with your two-step, it can be hacked just as easily as an encrypted password.