“Warning: Server Setup non-Apache” (GS 3.3.13)

[Tyblitz]

Here's the installatron service: https://installatron.com/getsimple/install (I think it's commonly integrated into cPanel providers).
Btw, I once successfully installed GS on an Nginx server, but it did take some tweaking (essentially rewriting htaccess rules in Nginx-compatible format)