Sometimes Horde won’t work after a cpanel update. You may receive below error, while accessing Horde.
HTTP error 503 The service is unavailable. Horde is unavailable while the system is setting the hostname.
Solution 1:
1. Make sure hostname is correct.
/usr/local/cpanel/scripts/check_valid_server_hostname
Solution 2:
1. ssh in to the server.
2. cd /var/cpanel/.application-locks
3. rm UpdateHostname\:USERNAME
4. /usr/local/cpanel/bin/update_horde_config –user=USERNAME
Refer : https://forums.cpanel.net/threads/horde-wont-load-after-update-to-11-52.503071/
Thank you 🙂