We can troubleshoot the issue about Unable to login on ISE through GUI. This is a very common issue. If you are not able to login on ISE through the GUI, in this case, you must login to ISE via CLI and try to run some commands:
We need to stop and start application services. Use the below command:
You can verify first that all services should be running:
bash
If the application service is running, then we need to stop and start the application services. Use the below commands. Before restarting, you must shift traffic from the primary to secondary, as it takes 10 minutes for the devices to come back up. My suggestion is to please perform this activity during the Maintenance Window.
# application stop ise
# application start ise
