More Mailers

I’m changing all 365 mailserver to port 25 to avoid the error because the protector with TLS enabled checks port 465 first.

While changing the some ports from default to 25 : the following warning suddenly appears (note: no servers are added only changing the port for existing servers)

WARNING : Only 1 more SMTP server(s) can be configured.

This is strange because if I don’t change the port to 25 it has no problems (or limits) at all.

Any idea why this warning is here, not adding any server, only changing some servers from default to port 25

Reply:

There's a limit on the number of mailers that can be used. We raised this
limit to 45 if I remember well. The unicity of the mailer is also given by
the port number, so changing it, cause the creation of a new mailer, which
reduces the number of mailers available.
The mailer count is taken from this command:
sudo sh -c "sendmail -d0.15 -bv root"