Thankyou. This fixed the MS account connectivity issue for me on Server 2016 Essentials (initiated by an expired remotewebaccess.com certificate).
Even after the above was fixed, there were still DNS lookup failures reported in Dashboard.log which were fixed by:
- Removing the default DNS forwarder (this was the IP address for an old gateway router)
- Temporarily unblocking IPv6 routing connections initiated from the router's WAN.
For those wanting to check Dashboard.log for DNS lookup failures, an example string follows. Note the typo: "conection" [sic]
CoreNet: Internet Conection test using DNS attempt to reach 2001:dc3:2f::f failed.
Historically the Anywhere Access wizard has required temporarily forwarding port 80 to the RDG during setup. This is the first time I've had to unblock IPv6 on the firewall during setup so perhaps it will be of use to others who've gone down the same rabbit hole.