Domain mapping not working


This site has Let’s Encrypt, so the install is in sub-directories. The problem is the front end does not display right, seems like a CSS (or other scripts) issues.

This is a new install, I’ve deactivated plugins one by one, the theme is wp 2016, didn’t install another theme until after trying everything else, it didn’t change anything.

I’ve tried every possible settings combination in DM plugin, with or without https, still the same.

If I delete the mapped domain, the site displays just fine on the sub-directory domain.

I even deleted the whole install and started all over again, still the same issue!

The main site, admin and sub-directories domains work just fine

Any ideas what might be the issue?

Another regarding the mapped domain, if I map the domain as https, I get this:

This site is not secure, continue at your own risk!

And to top it all, now I can’t even delete the mapped domain!