When trying to login using SAML, following error is observed:
Logon using SAML failed. Error: Cannot create a file when that file already exists.
Following event can be observed in the Security.evtx on Connection Broker:
Event ID: 4625
Sub Status: 0xC00000064
Task Category: Logon
Keywords: Audit Failure
CB is not a member of "Administrators" AD group.
Add computer account of all connection broker machines into "Administrators" AD group.