Moved to Business > SIEM forum for a better chance of a response
Are you attempting to login with the NGCP account, a locally created account, or an account that authenticates via RADIUS, CAC, Active Directory, or LDAP?
Are you getting any error messages?
Does your screen just blank out?
What version of software is your ESM running?
What Browser are you using?
Check first if you are able to login to CLI?
if you can try ps -auxf command and try to restart httpd service by service httpd restart and also for better clarification check cpservices is running are not.
It is always better to share the screenshot of what you observe.
As I understand from the explanation, login screen comes up but after taking the login credentials, it does not show anything else.
If you are running 9.5.x then this seems to be a known issue provided in KB86615, where sometimes user closes the window randomly, especially when it is stuck on loading policy editor.
After which when you try to login it will get stuck.
Check with the status of http process and corresponding logs
find / -iname httpd*
You will see logs corresponding logs related to httpd daemon
Check with messages file or NitroError.Log to see any abnormal messages coming up.
Restarting cpservice might help in this case, but beware, it might also lead to some detachment in db partitions for few tables.
Hope to see the screen where exactly it is stuck, to share precise information about the logs.
Thank you for your valuable information.
Issue got resolved by restarting the cpservices.