Hello again. I know very little about Python servers.
You need to make sure the headers are set correctly as described below:

Apache
https://github.com/2dengine/love.js/blob/main/.htaccess

NGINX
viewtopic.php?p=249988#p249988

Found another bug with Love.js that needs to be noted in the documentation: Causes a blocking crash when "path" does not exist on the user's hard drive.

Based on the third error message, my question is: did you package and upload your .love file correctly? The "main.lua" file of your game should be in the top directory of the love/zip file. Furthermore, you can specify which .love file to run in the love.js player using the "g" p...

Thank you for the clarification. I will take a look at this issue when I have a chance.
The same fix is available for Apache as an .htaccess file.

MrFariator, unfortunately it is not as simple as that. Steamworks SDK will require authentication, stats and probably a few other features in order to get your achievements working. My recommendation is to roll out your own system and don't waste your time with Steam.

MrFariator, do not be disheartened! I do not recommend using the Steamworks SDK anyways as it will make your games entirely dependent on the Steam client and infrastructure.

Hello ReFreezed,
I try to help out other developers just like you do with your open source libraries, but I am not obligated to do so.
The Steamworks SDK is a closed source commercial project so you can contact Valve if you need help with their SDK.

Most Apache servers have mod_lua, a module that supports the Lua language.
If your game does not rely on love.physics or love.math than you can probably re-implement your game logic in pure Lua.

Thank you for the comments. We stopped doing business with Valve so I cannot support this project.

Please note that at this time we are retiring the sworks-ffi library.
Thank you for all of your support!