Question Plesk Panel Extremely Slow and Shows White Screen Despite Server Resources Being Idle

[givemesomoney]

Server operating system version

Ubuntu 22

Plesk version and microupdate number

Latest

Plesk Panel Extremely Slow and Shows White Screen Despite Server Resources Being Idle​

Environment​

• OS: Ubuntu 22 LTS
• Web Server: LiteSpeed
• Server Specs: 10 CPU cores
• Plesk Version: Latest Version

Problem Description​

My Plesk panel interface is extremely slow and often shows a white/blank screen after loading for several minutes. However:

• Server resources are completely idle (CPU at 0-1%, 99-100% idle)
• Websites hosted on the server work perfectly fine and load very fast
• Only Plesk panel interface is affected (all Plesk-related screens)
• When I visit a domain already installed on Plesk, it works very fast
• In short: everything related to Plesk interface is extremely slow, but hosted websites are fine

Additional Findings​

• Found 6190 files in /var/lib/plesk/task-manager/runtime/ directory
• 219 failed login attempts in Plesk action log

Server Resource Status (from dstat):​

usr sys idl wai stl| read writ| recv send| in out | int csw
0 0 100 0 0| 0 0 | 20k 97k| 0 0 |1430 1374
0 0 99 0 0| 0 812k| 208k 4325k| 0 0 |3538 2581

Symptoms​

1. Accessing Plesk at https://domain.com:8443 takes several minutes
2. Browser shows loading spinner, then displays blank white page
3. Network tab shows net::ERR_HTTP2_PROTOCOL_ERROR on some requests
4. Some requests show Status 200 but still don't load completely

Temporary Solution Found​

The only thing that temporarily fixes the issue is killing all sw-engine processes and restarting:

pkill -f sw-engine
service sw-engine start
service plesk-web-socket restart
service sw-cp-server restart


However, the problem returns after some time and I have to repeat this process.

What I've Already Tried​

1. Cleared Plesk cache and sessions:
   • plesk bin cache --clear (command not found in my version)
   • plesk db "TRUNCATE TABLE sessions;"
   • Deleted old log entries
2. Restarted all Plesk services multiple times:
   • service sw-engine restart
   • service sw-cp-server restart
   • systemctl restart psa
3. Killed and restarted sw-engine processes:
   • pkill -f sw-engine
   • This temporarily fixes the issue but it returns after some time
4. Increased PHP/Nginx timeout values:
   • Set max_execution_time to 300
   • Set proxy timeouts to 600
   • Added timeout configurations
5. Checked for resource-heavy processes:
   • Found backup/migration processes running
   • Killed them but issue persists
6. Attempted to optimize database:
   • Optimized Plesk tables
   • Checked for slow queries
7. Security measures:
   • Installed fail2ban
   • Checked SSH logs for brute force attacks
   • Found significant attack attempts

Logs Checked​

• /var/log/plesk/panel.log
• /var/log/sw-cp-server/error_log
• MySQL process list

Questions​

1. What could cause sw-engine processes to hang/freeze regularly?
2. Is there a known issue with sw-engine-fpm becoming unresponsive?
3. How can I permanently fix this without having to manually restart services?
4. Are there any specific Plesk settings I should check for Ubuntu 22 + LiteSpeed combination?

Any help would be greatly appreciated as this is seriously affecting my ability to manage the server.


Thank you!

 

[Sebahat.hadzhi]

Hello, @givemesomoney . Could you please check /var/log/httpd/stderr.log and confirm if there are any entries suggesting you hit LSAPI_CHILDREN?