Can't Enroll IG on SCCM

Hello,

I'm installing OMIMSSC for SCCM. When I attempt to Enroll a Console, it shows IG "Check Integration Gateway details and try again."

I'm fairly certain I've checked every piece of the Install guide.

The credentials are correct.
I can ping between the appliance and the SCCM/IG server.
I can browse to the IG IIS site https:// sccm:8455.
I can access the shared folders at \\sccm
The user account is an SCCM administrator.
The management systems have DNS entries.
The Execution policy for the IG user account is Unrestricted.

Should the IG be on a separate VM or can it be on the SCCM server? The prereq check for the IG installation seems to suggest that it should be on the SCCM server but parts of the documentation reference multiple servers.

Are there logs that people tend to rely on for troubleshooting this?