Need Help - One Member Can't Connect After Forge/Quark Install

Hey guys! 2 friends and I have a 1.14.4 server that we recently switched from Spigot to Forge because there were a couple mods we wanted to have. I got the latest version of Forge (28.1.96) installed, then installed the Quark mod (r2.0-199) and it's dependency, AutoRegLib (1.4-35).

We had a few problems at first because neither of my friends had Forge or Quark installed client-side so neither of them was able to connect, but they got both installed and one of them is now able to access the server without problems. The other one, though, still can't access the server at all. After trying everything I could think of (including updating Java on his computer), I have no idea what the issue is or how to fix it. Every time he tries to connect he gets the "Connection reset by peer" error, and the server throws a "mismatched mod list" error.

I've attached screenshots of both his mod list and the server's mod list, but I'm not seeing what it's complaining about lol. At first I thought it might have been his Forge version, since the server is running 96 and he's running 92, but my other friend is running 92 as well and I'm running 90, and both of use are able to connect without a problem. If anyone can help us out we'd be immensely grateful!

Here's the server log -- down at the bottom you can see where he tried to log in twice (lines 286-293).

His mods folder:

The server's mod list:

Wait, really? All of the Forge files? It didn't even occur to me to try that, since mine stay in my mods folder and I wasn't having problems. Does it matter where he moves them to?

Well yeah, but all it does is pop up a warning when you start the game that it isn't a valid mod file...it shouldn't be preventing him from connecting to a server, right? My forge installer is still in my mods folder (just cuz I've been too lazy to bother with it ) and it hasn't prevented me from connecting to the server.

I guess I should have mentioned that he has no problems running the game in single player, he just hasn't been able to connect to the server since we installed Forge and the Quark mod on it. He's also the only one of us running a Mac, if that makes a difference for the server at all. (I wouldn't know, I try not to touch 'em personally! xD)

Haha fair enough!

I think he just copied everything in there at once. I put it in there before I run it because I've had issues in the past...long and totally irrelevant story lol.

So any ideas about why he isn't able to connect to the server? x.x

Hey Roman,

1) The client shows a "Failed to connect to the server: Connection reset by peer" error when he tries to log in. It was also giving him a warning when he hovered over our server on the Multiplayer screen - I'll attach a screenshot of that down below as well.

2) He's definitely using the correct (forge) profile - I actually made him send me a screenshot of his launcher to be absolutely certain of that lol.

3) He now has forge version 28.1.96 installed, which is identical to what's on the server. I just sent him a message telling him to take the forge files out of his mods folder and try again -- I assume by that you mean all of the forge files including the universal file, right? Does it matter where he moves them to, or do they just need to be out of the mods folder?

Edit: He removed all forge files from his mods folder and restarted the game & launcher but nothing's changed, client and server are both still getting exactly the same errors as before.

Thanks for the reply!

Client-Side:

Server-Side:

(I linked the full log in my original post, but here's the specific log entry in case it helps)

We got it fixed. He ended up installing JarFix, and that solved everything lol.