When trying to add the SMP Server to the Internet Gateway it fails with the following error in the logs:
Web exception occurred during Server certificate request - the underlying connection was closed: An unexpected error occurred on a send.
ITMS 8.5 RU3
The SMP erver and the Internet Gateway server were both configured for use with TLS 1.1 and TLS 1.2. by default. They do not have settings in the registry.
We added the registry settings even though they should be enabled by default and this resolved the problem.
NOTE: Used IISCrypto and let it add the registry settings to the server.
195561 Unable to add SMP server to CEM Internet Gateway Server List: "The underlying connection was closed: An unexpected error occurred on a send.."