REST API OAuth is thowing error- Session contains no certificates - Untrusted, Some times not always

[snowarchitech1]

When we are calling the Outbound Rest API, sometimes we are getting the "Session contains no certificates - Untrusted".

Strange is same user it is working and  for the same user sometimes it is failing. getting the "Session contains no certificates - Untrusted".  If we take the Same oauth token and try from Postman it is working. When we try from Servicenow it is failng.

But when we try from the Postman it is working. Kind of confusion since it is working sometime and sometimes it is failing.

[Dawid K1]

We have received the same error and in our case it was related to the "SSLPeerUnverifiedException: peer not authenticated" exception, which is described in this KB SSLPeerUnverified exception in third party applications after SSL cert update in ServiceNow - Suppor...

Normally, it should no longer be the case, but if someone is messing with certificates on the 3rd party application, it might result in "Session contains no certificates - Untrusted" error.