Not connect to mail from i-mac devices

Well, this strange case happens to me, from any other client, such as thunderbird, everything is perfect but... from two new i-mac devices, it does not connect to mail, testing, I have seen that, if I deactivate Firewall then it does connect, if I activate firewall does not connect.
But the imap firewall ports are correctly open, 993, 465...etc...otherwise it wouldn't work from Thunderbird for example.
And I don't like having to have the firewall disabled.

Any ideas? Because for me, it's the strangest thing I've ever seen...

Regards.

Any iddea or suggestion?

Regards!

Are you supporting STARTTLS ports in addition to the SSL/TLS mail ports?
143 for IMAP, 25 for SMTP, 110 for POP3, 587 for submission.
I can't say how your Mac clients are set to connect to the server, but they can support both STARTTLS or SSL/TLS.

Are you supporting STARTTLS ports in addition to the SSL/TLS mail ports?
143 for IMAP, 25 for SMTP, 110 for POP3, 587 for submission.
I can't say how your Mac clients are set to connect to the server, but they can support both STARTTLS or SSL/TLS.

First of all, thanks for answering and apologies for the delay in answering, I spent a few days without being able to answer and the email notification entered my spam folder...

Indeed, in firewall I have those ports open, this is a list of the ports (I have removed those that are not relevant and/or are used for other things):

tcp
IN: 20, 21, 25, 53, 80, 110, 143, 443, 465, 587, 993, 995,
OUT: 20, 21, 25, 53, 80, 110, 113, 443, 143, 993, 995,

I'm seeing, 465 and 587 are not in OUT but they must be in IN not OUT (correct me if I'm wrong).

What I commented, thanks for the answer and sorry for my delay in answering, between the fact that I could not connect for a few days and the email notification arrived at spam...

This is a topic that has me intrigued, indeed, a Mac connects just like any other (I think...)