502 Bad gateway while logging to the WP admin panel

Thanks neiljay for the help.

It concerns me because the 502 error occurs only when I try to log in. Instead of the view of WP admin panel after log in attempt, I got the error. Besides that, site works fine.

I have only flexible mode on because my host provider doesn’t allow me to install cerificate on the server in my billing plan. Also that is why I use only SSL certificate issued on Cloudflare. I’m going to change provider in the future so I will change to full strict. Thanks for tips.

I have contacted my host provider and I got information that from their side everything is fine. I am not sure whether there may be a problem with HTTPS protocol during log in to the panel. I have HTTPS rewrites in the WP settings turned on as well.

I am really suprised because I didn’t find similar problem on the web.