After just spending a few hours trying to get RedGate SQL Monitor to monitor our Windows 2016 SQL Server in AWS I though I better record the solution!

We already had a rule in place on the AWS firewall which should allow all traffic from our office so this was unlikely to be causing an issue.

We had enabled inbound rules in the windows firewall for RPC/WMI but to rule this out we disabled the firewall entirely (temporarily) which made no difference.

We tried connecting using the IP Address and hostname. Tried using .\username hostname\username,\username and received a variety of errors including;

Number: 0x80070776
Facility: Win32
Description: The object exporter specified was not found.

Number: 0x80070005
Facility: Win32
Description: Access is denied.

The end solution was adding a record to C:\windows\system32\drivers\etc\hosts with the public IP and hostname (not fully qualified). Then I was able to connect just fine using \\hostname\root\cimv2 with the username .\username

It seems to be a NAT related issue despite the AWS server having a public IP.