Custom Domain

You need to remove any references to the old mail records for MX at the host first!!

Then add the new MX entries exactly as in the email sent to you (ignore the online settings they are wrong)

Then add the TXT entries as new ones as in the email sent to you.

Finally at the new CNAME as in the email sent to you.

This can be done right in the Domain DNS dashboard control, depending on what dashboard control panel your host has.

Cpanel is by far the easiest one to navigate thru.

If you feel unsure about any of the steps, your hosting provider should be able to do this for you, try sending another support ticket to your host and this time copy the settings from the apple email custom domain setup, you might get another team member that will help you.

Just to add to my comment:

Please be aware of the following settings, if not already supplied in the Apple custom domain setup email;

MX settings

Priority 10 TTL 3600

I've been messing around with this for the past week, and I think I'm at the same point you are.

The problem, and it seems like a very significant problem to me, is that the instructions from Apple about what to change at my registrar's website and what is actually shown at my registrar's website differ significantly.

These settings are found on the Web.com registrar under Advanced DNS settings, and there is a warning not to mess with them if you don't know what you're doing.

So I filled out a Work Ticket to Network Solutions (Web.com), attaching Apple's instructions regarding how to set MX, TXT and CNAME. From them I got back an email saying, basically, I had to do it myself, and giving me a link to a file explaining what this stuff is. You can view this file here: https://customerservice.networksolutions.com/prweb/PRAuth/app/WebKM_/JfLhd8LVz0a16-h3GqsHOCqqFky5N_vd*/!autoThread0?pzuiactionzzz=CXtycX1jYjNmOWRhMjM1ODQyNmE2OTc3OTZmNTJmNDA5NjExZGMxYmU0MmE0Y2M5YmM2YjkyNGRmYmMyNmNiNDE0ZTY5OWExZWVmZTk3YWJiOWU1ZTQ3NjJlNzdiYzE0NWRkNmI4M2U2MWQxMjNkZTA0NmY4ZWJjOWI2ZTQ1MDMzOTQxYmQ2ODJiZjViN2NiMGI1OGU2N2ZmN2Q3NzExYjQ0NDQ4Zjc2ZTZiYjhkNDBkYjEwMzA0ODNlMWRhZTZkM2JmMDg%3D*

My registrar is Network Solutions. Apple instructions says to update TXT. I can't find any location on the Network Solutions DNS pages that has an TXT designation, though it does have DMARC. But I don't know what that is, either.

So it seems to me that this idea of Apple's to have the customers change their own DNS settings at their domain registrar's website isn't practical.

Is there an expert out there who can either do this for me (preferable) or look at the Network Solutions sites (I have screenshots) and explain in exact detail how to do it?

Yeah I'm not going to do any of this.

The instructions from Apple do not include sufficiently detailed information, since (for one thing) there isn't any TXT place to change anything on the DNS settings at Web.com (network solutions).

It ain't broke, I ain't messing with it.