503 error on sites using LiteSpeed

Issue

• All websites down with 503 error 
• The following can be seen this in the error log.

  [NOTICE] [50786] [T0] [203.0.113.2:40566:HTTP2-17#APVH_example.com:443] Max retries has been reached, 503!
  [NOTICE] [50786] [T0] [203.0.113.2:40566:HTTP2-17#APVH_example.com:443] oops! 503 Service Unavailable
  [NOTICE] [50786] [T0] [203.0.113.2:40566:HTTP2-17#APVH_example.com:443] Content len: 0, Request line: 'GET / HTTP/1.1'
  [WARN] [50786] [T0] [203.0.113.2:40566:HTTP2-17#APVH_example.com:443] 503 error on top of 503 error happened, disable custom 503 error page.

Environment

• LiteSpeed

Solution

Try temporarily switching from LiteSpeed to Apache.  In case the error has gone, consider contacting LiteSpeed support team.

Useful links

Troubleshooting 503 Errors

LiteSpeed 503 service unavailable error – Here’s the quick fix

Max retries has been reached, 503!