cPanel blank after login

[ReiJu]

One of my servers have this strange behaviour:

1. cpanel-login-page shows perfectly
2. after login, only a blank page shown on the browser
3. even when i tried to login to cpanel via whm, i still got a blank page

I tried to upcp --force but still no luck. Rebooting the server seems to resolves this problem, but only temporarily. After the server runs about a couple hours, the blank behaviour reoccures.

I get this message (from /usr/local/cpanel/logs/error_log) everytime I accessed the blank cpanel:

Can't call method "warn" on an undefined value at /usr/local/cpanel/Cpanel/Sys/Hostname.pm line 71.

Please tell me what to do.

[cPanelDon]

One of my servers have this strange behaviour:

1. cpanel-login-page shows perfectly
2. after login, only a blank page shown on the browser
3. even when i tried to login to cpanel via whm, i still got a blank page

I tried to upcp --force but still no luck. Rebooting the server seems to resolves this problem, but only temporarily. After the server runs about a couple hours, the blank behaviour reoccures.

I get this message (from /usr/local/cpanel/logs/error_log) everytime I accessed the blank cpanel:

Can't call method "warn" on an undefined value at /usr/local/cpanel/Cpanel/Sys/Hostname.pm line 71.

Please tell me what to do.

Does this affect multiple accounts or just one cPanel user? Please consider submitting a support request so that we may assist with investigating the issue. Please also let me know your ticket ID number when available.

[ReiJu]

This was affected all users in the server.

Fortunately the problem solved. cpanelsrvd complaints about the server's hostname which is not FQDN. I don't remember changing the server's hostname, because cpanel installation process (circa a couple months ago) wasn't complaint about anything.

So, changing the hostname into FQDN and restarting cpanel daemon fixed this issue.

[cPanelDon]

This was affected all users in the server.

Fortunately the problem solved. cpanelsrvd complaints about the server's hostname which is not FQDN. I don't remember changing the server's hostname, because cpanel installation process (circa a couple months ago) wasn't complaint about anything.

So, changing the hostname into FQDN and restarting cpanel daemon fixed this issue.

Thank you for the follow-up detail and resolution information. Were any other corrective measures attempted or performed, i.e., anything other than correcting the system hostname?

[ReiJu]

The complete steps are (as long as I can remember):

1. upcp --force
2. reboot (fixed but then reoccured)
3. upcp --force again (still no luck)
4. doing some reading
5. change hostname
6. restart cpanel daemons (fixed)

No critical action performed, I guess, other than changing the hostname.