eM Cliet (paid) refuses to accept my credentials, even though the IMAP and SMTP configurations haven’t changed except for my password which I changed recently. I can log into my email account’s web site. I changed password twice in the last two days just to be absolutely sure I have control of my account. I have 2-factor authentication for it.
I ran Diagnostics in eM Client and it says “Your credentials were rejected” for both IMAP and SMTP. I’m using the ports recommended by my email company. I’ve tried both “Force usage of SSL/TLS” and “Use SSL/TLS if available” (Force is recommended).