I have tried to open SharePoint portal with Claims Authentication that was worked properly! but Suddenly, I got the below error:
An exception occurred when trying to issue security token: The requested service, ‘http://localhost:32843/SecurityTokenServiceApplication/securitytoken.svc/ actas’; could not be activated. See the server’s diagnostic trace logs for more information.
I checked the log file and Event Viewer and seems that
Secure Token Service is failing Continue reading An exception occurred when trying to issue security token in SharePoint