The following error is returned when adding a Site Server to the Internet Gateway (under the "Servers" tab):
Failed to validate server certificate
ITMS 8.7.x, 8.8.x
Misconfiguration in the Site Server's IIS binding (specifically port 4726), port 4726 is not open in the Site Server's firewall, or a mismatch in the assigned SMP Server CA certificate.
Here are some suggestions on what to check:
Test-NetConnection -ComputerName [SiteServerIP] -Port 4726 from the Internet Gateway server to ensure the port is open and reachable. The results will be something like:
ComputerName : ServerName
RemoteAddress : 1.1.1.1
RemotePort : 4726
InterfaceAlias : Ethernet0
SourceAddress : 1.1.1.2
TcpTestSucceeded : True
NOTE: If port 4726 is opened, it should return TcpTestSucceeded : True