Bad Gateway coming randomly after adding service


I have a bit strange issue with Traefik installed from TrueCharts on TrueNAS.
The issue is that after adding Exchange Server 2019 that previously was passed through HAProxy i got after some time Bad Gateway error (502). Funniest thing is that it recovers after some time and gets broken and thats how I can get spammed with alerts that my service is down :sweat_smile:

Do you guys have any idea what's happening?
Exchange Server on WS2019

Share your full Traefik static and dynamic config, and docker-compose.yml if used.