Portal Blocks Mod Server Crash

Hello, I am new to the forums, so if I posted in the wrong section or anything else, I am sorry.

I have a problem with mods on my server. I am trying to mount iChun's Portal Gun mod (with iChun Util) and the Portal Blocks mod. Thing is, after a long time of waiting, the server just crashes. The log says that it 'threw an exception'. There are no different versions of the mod on Aternos, but it seems to be the latest. The versions are the same both on Aternos' mod picker and on CurseForge.

Anyway, I hope you can help me pin this issue down. Thank you in advance.

By the way, if you need the Log or anything, just ask me.

Here it is.

https://mclo.gs/kjeB0lk

Sadly, it looks like the mod is no longer updated. But as I am not a computer expert, may I ask what is wrong exactly?

Well that's weird... why does it work on normal Minecraft Forge (singleplayer) though?

(I am sorry for too many questions)

Okay, I understand. I will try to contact the author of the mod anyway, now that I think about it... Thank you for your help!