I've updated my local Sugar instance (hosted on vagrant) from 8.3 to 9.0. The first time I used it, I was able to log in with no problems. When I reloaded vagrant and tried to log in again, I got an error 500 "Invalid IdP configuration". Then I noticed that in config.php I had
'authenticationClass' => 'IdMSAMLAuthenticate'
Since in the previous Sugar version this setting was blank ('authenticationClass' => ''), I did the same thing here. Now, when I try to log in I don't get the "Invalid IdP configuration", but instead the login page keeps reloading in an infinite loop. Since SAML is not used in localhost, I tried 'authenticationClass' => 'SugarAuthenticate', but that had no effect. I also tried I tried deleting the browser cache, as recommended in a similar post, tried deleting Sugar cache using "