Ok, so this is a weird one for me, so I'm going to be as exhaustive as possible.

• I built a server at home and plugged it in.

• It has an ethernet connection to a switch, then the switch to the home router. (I use a french livebox).

• It runs on ubuntu server and the services are on docker.

• I use traefik for reverse proxy.

• All services use the labels for traefik.

• The corresponding ports are forwarded via the router's administration interface.

• I use hetzner DNS (they updated it to the console lately).

• A and AAAA records are made and propagated.

So here is the problem:
When on wifi, I can access the websites hosted by the server. Laptop, Desktop, Phone they all work.
But the second I switch the phone to it's own data (wifi off), then the sites are unreachable. I get "connection reset" messages and endless loadings on refresh. When I share the phone internet to laptops, they also fail to find the websites.
I tested it from a friend's house, then went on their wifi and the websites can still be reached.
The only thing that can't reach them is phone data. And for the life of me, I can't pinpoint the source of the problem...

I'm pretty green when it comes to System Administration and Networking, so if anyone has an idea about what is going on, I'll be happy for the help !