520 error

I am running a few Wordpress websites with Cyperpanel (v2.0) and OLS (v1.7.5) on an Ubuntu 20.04 server (4GB, 2 vCPUs) at DigitalOcean. There are also a couple of nodeJS apps running on the same server. I just recently set up all the sites. I am the one generating most of the traffic right now...

Hello! I'm using openlitespeed with directadmin. I am getting 520 errors on some websites. Could a wrong configuration on the openlitespeed side cause this? where should I start debugging? I've been trying to solve this problem for a long time. Note: Today I upgraded the openlitespeed version...