How to setup autodiscover for email?

I am a bit confused how to setup autodiscover for email...

I have a mail server and I want everyone to use the server domain as I have SSL on that, and not use their own domain as the mail server.

So for example, domain1.com has MX records myemailserver.com.

If I set the MX record to mail.domain1.com then Thunderbird autodiscover finds it OK. When i change MX record to myemailserver.com then Thunderbird says its failed to find the settings.

Basically any domain I have my email server as the MX record I want autodiscover to find the settings OK.

Also, Apple Mail just doesnt work regardless of MX record. What do I need to do to get Apple Mail to autodiscover?

I have not tested Outlook as I dont have it.

Thanks