Mac Thunderbird zoho e mail account issues

Mac Thunderbird zoho e mail account issues

I have issues with a user account on thunderbird e mail client who suddenly does not receive emails, when you click get messages we get an error "sending of password for user ......did not succeed, mail poppro.zoho.com responded service unavailable" after click of it saus login to poppro.zoho.com failed, if we click enter password we get the message username did not succeed, user already specified.
We did not change any settings and other users work ok only this account has issues.
We tried user to sign in on another mac and we get the same error messages.
What is going on ? yesterday there were issues with SMTP service is pop having issues today?