[SOLVED] - Nginx RPM and Microsoft 365 credentials - 502 Bad Gateway

[davidm40]

Hello there,
I'm desperatelly trying to make my app work with Nginx RPM but I'm facing an issue ; While I assume there is something like proxy_pass or something like this I must add in the Advanced config of Nginx RPM, I don't know what exactly.
The diagram below explains the problem. When I try to authenticate to my application from the outside (internet) using my Microsoft M365 credentials, it sees like the proxy needs a special parameter to handle it properly. While when connecting to the app from the inside network (and then bypass the reverse proxy), I can successfully authenticate to the app using my Microsoft 365 credentials.
Has anyone ever configured the M365 auth through RPM ? Thanks a lot

[davidm40]

EDIT :
Adding these into the Advanced menu, under Custom Nginx Configuration solved my problem :
proxy_buffers 8 16k;
proxy_buffer_size 32k;