Website login pages return 503 errors with Imunify360 version 8.2.5-1

Symptoms

After Imunify360 updates to 8.2.5-1, websites returned 503 error messages.

LiteSpeed returns a 503 error message:

Apache's error_log ( /var/log/apache2/error_log ) returns the following: 

Error on sending request(POST /json HTTP/1.1); uri(/index.php/json) content-length(10): ReceiveAckHdr: nothing to read from backend 

Description

Imunify360 can apply updates automatically via its cron or cPanel updates.  A recent update is causing some website login pages to return a 503 error. The Imunify360 team is aware of this problem and is investigating it.

Please follow the Imunify360 changelogs to determine when the issue DEF-30956 has been resolved.

Imunify360 changelogs

Workaround

Downgrade Imunify packages and disable the rollout.

yum downgrade imunify360-php-daemon imunify360-php-i360
yum config-manager --disable imunify*rollout*