Varnish docker and nginx, plesk

Description

I'm facing an issue with Varnish running in a Docker container within a Plesk environment. The setup works perfectly on the staging server, where Varnish runs in front of Nginx, and performance is fast. However, after migrating to a new server with Plesk and an identical setup, Varnish refuses to start with the same configuration and parameters.
Ports: 80 for HTTP, SSL on 443
The issue: I understand the conflict of having the same ports on both services, but I'm trying to point Nginx to port 8080 as specified in the Varnish config file. When I do this, it doesn't work.
What I need:I'm looking for someone who has experience with Varnish in Plesk/Docker environments and can resolve this issue quickly. You should have a "hit the ground running" attitude and be able to solve this in 1-2 hours. This is not a multi-day or week-long project, just a quick fix for someone who knows how to address it.
Key Skills Needed:
1. Varnish configuration and troubleshooting
2. Docker and Plesk setup
3. Nginx configuration knowledge
Please apply if you're confident in your ability to resolve this issue quickly and efficiently.