Unable to authenticated using secured protocol

[anton_latvia]

Hello,
Suddenly the following bug appeared - customers started to complain, that they are unable to connect to IMAP server using secured (TLS or SSL) connection - they are unable to use secure authentication. I have checked - none of certificates have expired, tried upgrading courier, but it did not help. Thunderbird is giving the following error message:

You can not login to <server_name> because you have enabled secure authentication and this server does not support it. To Log in, turn off secure authentication for this account.

Clients are claiming this was working before. Can anyone give me friendly advise?

Anton.

[benito]

Try unchecking the checkbox right under the SSL list option.

[anton_latvia]

Where is that? Which option do you mean?

Anton.

[benito]

I have it in spanish, hope you can find this option in yout version.

[anton_latvia]

Yeah, this is what client had to disable and he also stated, that some time ago it was working fine, even with this option being checked. And that was actually my original question - is it possible to have secured authentication or not..