I don't know if my title is very explicit but I made a diagram of our stack to explain my situation :

I am currently working on migrating a platform to a Docker environment (mysite.subdomain.com on the diagram).

My problem is the following: when I click on a link or redirect from mysite.subdomain.com to othersite.subdomain.com or anothersite.subdomain.com, I get the following error from traefik:

If we try to access othersite.subdomain.com or anothersite.subdomain.com directly without first going through mysite.subdomain.com, it works.

If we try to access the URL from mysite.subdomain.com to othersite.subdomain.com with Curl or Internet Explorer it also works (the redirection works).

If we try to access an URL on internet like google.com for example, it works from any browser.

What i don't understand :

We click on a classic HTML link (a href=""), the URL in the browser changes well but the routing does not seem to behave in the classic way as if we were entering the URL by hand in the browser.

Our question is: Is there some kind of "network cache" on recent browsers that make sure that the navigation does not start "from scratch" when you are in the same domain?

If so, how can this be prevented? Is there a setting to be made in traefik? Haproxy? A setting to be made on Apache ?

Thank you in advance !

EDIT 05/04/2022

By clicking on the link with internet explorer we have two tcp sockets which open and the download works. On the other hand with chrome and firefox, only one tcp socket opens and we get a 404 from traefik. which makes us think that all trafik passes through the same socket.