502 Bad Gateway after Microsoft login

[Toni-SI]

Hi!

My customer is using local web app, running on IIS. That apps offers an option to login with Microsoft account. So when I choose that option and log in using MS account, i get message 502 Bad Gateway, openresty.

Then I return back to login page and pick Microsoft login again, after that I am automatically logged in.

So I always need to somehow "refresh" web app, to be successfully logged in.

I am not expert for custom configs, however I tried to extend timeout, also to change SSL cert from bought one to free Lets Encrypt, none of those helped.

Kindly asking for advice :)

Thanks.