As per the photos the issue is intermittent reported by our monitoring server zabbix.
running tests to non proxied site is fine https://shop.scanimals.net but the cloudflare proxied one as per topic post, I see failures…
A little python script to test and report http status codes
to live site (non proxied)
root@monitor:~# python3 /opt/scripts/100_requests2.py
Total successful requests: 100
to cloudflare proxied address
root@monitor:~# python3 /opt/scripts/100_requests2.py
Total successful requests: 98
Non-200 responses or errors:
Attempt 4: Status 520 -
Attempt 10: Status 520 -
So for other peoples benefit, I tried everything to fix this issue, spent 2 weeks of many 4-8hr stints.
I eventually put nginx in front of apache and now its stable.