We've had Portal for ArcGIS (first 10.3.1 then 10.4.1) running for almost two years. For at least the past year, it has been integrated with our ADFS system for single sign-on. Last week (although it could have happened earlier than that) we started getting this error:
Unable to login using Idp Unable to validate SAML response
According to our IT department, nothing has changed on our ADFS server, and our site certificates have not expired (they should be good through some time in 2019). I have not been able to find any way to resolve this problem. We are totally unable to sign in to Portal to do any management tasks.
Can someone offer any suggestions on what we need to do to fix this?