Error while passing through the Nether portal.

[scor78]

Going through the portal (Nether->OW->Nether) causes the server to crash. Going through the portal (OW->Nether->OW) works fine.
The server is running on Fabric MC 26.1.1. My game is on Fabric 26.1.2. Without this mod everything is ok.
(I use mods: Xaeros minimap/worldmap, sodium, lithium, iris, jei, tweakeroo, litematica, malilib, modmenu, better f3, ukus armor hud, cloth config api, worldedit)

[replaceitem]

This is a client-only mod. Do you have it on the server or client? On the server, the mod should do nothing. On the client, something would have to go very wrong for the server to crash. This mod does no communication with the server, and interferes with no packets. If you want, you can send a crash log, but I have my doubts that this is the actual cause.

[scor78]

I have it on the client. I wrote about the server just for information.
(I was surprised that this (client) mod can affect this and I think I wrote a report first. I've been playing MC continuously since 2011.)
edit:
I'm stupid for not trying the single player game. Portal navigation is fine, but when I click the smiley icon in the bottom right (inserting a smiley in chat), the game crashes. I have no idea where the error could be. Am I missing some API for this mod? I've used this mod before and had no problems with it.
Error message from MC (original launcher, Win11):

Game crashed: rendering screen
Error: java.lang.NullPointerException: Cannot call 'net.minecraft.client.gui.components.WidgetSprites.enabled()' because 'this.sprite' is null

[replaceitem]

Alright, I was confused because you mentioned it causes the server to crash. The crash message shows it's the client though.
It looks like this issue can only occur in combination with other mods, or a resource pack that adds a custom symbol chat tab.
It should be fixed in the next version.