Internal Exception: java.io.IOException: Connection reset by peer

Aternos Software: Forge

MC Version: 1.12.2

When my friend tries to join my Aternos Server, she gets the following error:

Internal Exception: java.io.IOException: Connection reset by peer

I tried deleting her player data as said in other threads, but the problem still persists, and she gets kicked after a few seconds.

Here is the log file: https://mclo.gs/5G0JOTr (This was when she tried joining after I deleted her player data)
Please help!

1. I have checked (by restarting tab) and it said it was still online.

2. She has tried the DynIP but the problem persists.

I followed the following article: https://support.aternos.org/hc…72-Connect-to-your-server

If this will help, our server is a pixelmon server, and I just found out that they keep addtional player data in the pokemon folder (world -> pokemon). Will it fix the issue if I delete the minecraft player data along with the pixelmon player data as well?

I have tried deleting all of her playing data (minecraft, pokemon, advancements, etc.) but the problem still persists. She still gets kicked 30 seconds after she joins with the same error as before. If this will help, I'll list a the mods we have for our server.

Server Software: Forge

MC Version: 1.12.2

Mods:

Backpacks 3.5.8 (https://www.curseforge.com/minecraft/mc-mods/backpacks)

Mr.Crayfish Furniture Mod 6.3.0 (https://www.curseforge.com/min…/mrcrayfish-furniture-mod)

Future Versions V1.2.2 (https://www.curseforge.com/min…ds/future-minecraft/files)

Pixelmon Reforged V7.2.2 (https://reforged.gg/)

Pokelucky - Reforged Version (https://www.curseforge.com/minecraft/mc-mods/poke-lucky)

I made a new vanilla server, and she has no problems with joining. It doesn't kick her either after a prolonged period of time. She could also join multiplayer servers such as hypixel and mineplex with no issues.

She has tried to reinstall her pixelmon client (reinstalling the mod) but the problem still persists. We also tried matching her forge version with the version on the server software, but that didn't solve it either. We even tried updating her pixelmon to the latest version (both on the server and for her) but she was still getting kicked 1-2 minutes after joining for the same error.