One really good place to start with Exchange diagnostics, is in the shell. Run this:
Get-NetworkConnectionInfo
and verify everything. If you see extra IPs (v4 or v6), if you see wrong IPs, if you get error messages, check your server’s IP settings and then restart Exchange, lots of things stop failing this way.
One of the oddball things you can discover using this, is that Exchange may be using the virtual switch NIC of a Hyper-V install. That can be a bear to deal with; in at least one case, the simplest solution was to fix Hyper-V rather than change the configuration.