So.. I'm using Fabric installation and install it's mods, so I could play Aternos server with my long distance boyfriend. But he and I have exact same files and same everything.

He got in fine but, I ran into this "Network Configuration task Not Supported: BetterCombat: Config" So I spend last 2 hours reinstalling mods, then fabric installation everything but it's still not working.

Here's my mods list along with server's list.

I don't really know how to find the logs with error issues so If anyone guide me how to do it then I'm appreciate it!

This is most definitely an installation problem.
Please join our discord server and go through the troubleshooting guide.