Hello.
Within the last 36 hours or so from Sept 25, 2025, our AGOL hosted feature services (at least two of them) have started rejecting connections from our Web API. We are using oauth authentication, passing a client id and password to GetToken, then appending the token to subsequent requests to the feature services. The key pieces of the response back from the AGOL hosted service are "The SSL connection could not be established, see inner exception." and the inner exception "Authentication failed because the remote party sent a TLS alert: \u0027HandshakeFailure\u0027."
This is true for multiple servers running Windows 2012 R2. However we have a couple of other servers running Windows 2022 and 2025 where the exact same code is able to connect successfully. I have verified that our Windows 2012 servers are using TLS 1.2. Those same servers are able to get Tokens from the GetToken endpoint but cannot connect to the Hosted Services. For at least the past 6 years prior, the API was happily connecting multiple times per day. This is a recent event.
Any help is appreciated.
Thank you
