How to fix error 500 when logging into opencart3 admin?

Question

PHP

Good day! However, moderation has become harsh.
we have opencart 3.0.2.0 with one of the journal themes, dedicated server, Ubuntu 16.04.2 LTS "Xenial Xerus", VESTA control
panel VESTA in the domain settings the following parameters are set - WebAPACHE2 template installed phpfcgid, ProxyNGINX support - Proxy template - cached, changes were made to the server configuration and database indexing was done by our freelancer.
Specifically:
set memcached
system cache - a day
of query cache - 5 minutes (since you often update products)
added indexes to the database
After that, there was a problem with the display of the site, I had to turn off the cache of the journal theme. After that, the site started working, but it was no longer possible to enter the admin panel - error 500.
It is possible that after some action that I do not know happened.
What can be done? Where to look ...
At the moment, the octopus file manager has stopped running, I wanted to look into the logs ..

[email protected]:/opt/sprutio# ./run.sh
docker-version.sh: line 7: printf: 0-ce: invalid number
Removing sprutio_cron_1...
Recreating 79352afe9a_79352afe9a_79352afe9a_79352afe9a_sprutio_cron_1...
connection error: desc = "transport: dial unix /var/run/docker/containerd/docker-containerd.sock: connect: connection refused"

[email protected]:/opt/sprutio# # ps -ylC httpd | awk '{x += $8;y += 1} END {print "Average Proccess Size (MB): "x/((y-1)*1024)}'^C

ps. I noticed a strange load on my computer when you go to the site, 40 percent is loaded ((

website

edeal.market