hi Rafie -
Check if the app-server has started.
You can verify it via: request nms all stauts - to see if all the nms processes hava started or not.
If you are still having an issue with GUI access, you can stop and start all the processes.
request nms all stop - followed by - request nms all start - may do the trick.
If not, open a TAC Case with Cisco, so it can be looked into.
Btw - if this is a new install, 20.4.x, is not a long term release.
It is recommended to go with 20.6.x (20.6.3 and above)
HTH
