Backend error throught HAproxy

I use a HAproxy as reverse proxy to make my Librenms available from internet. In local, Librenms works great, the validate script doesn’t return errors. but from internet I can’t see my graphs, devices and do modifications.
Do I miss a step ?

It seems to be a problem of rights. When I enter the URL with the ID of my device, it print well. Do I have to modify something in apache ?

Do I’m the only one to encounter this error ?

I experienced a similar error using Sophos UTM Web Application Firewall to publish my Librenms instance. I enabled rewrite for headers and cookies and that fix most things. I am still unable to create API tokens using proxy access and have to access Librenms directly to do that.