Mod conflicts

Mod is present on one side only (client/server)

What the log looks like

mod rejections?
missing mods?:
this server has mod[^\n]{0,40}that (?:you|your client) (?:do|does) not
server has mods that require

How to fix it

  1. Install the listed mods on the side that is missing them
  2. Client-only mods like minimaps do not belong on the server
SeverityBreaks something
CategoryMod conflicts

Check your own log

Related errors

Mod conflictsAE2 Terminal Crash with REI: TextField.isFocused() NoSuchMethodErrorUpdate both Roughly Enough Items (REI) and Applied Energistics 2 (along with Cloth Config and Architectury APIMod conflictsApplied Energistics 2 Server Startup Crash (WorldData IllegalArgumentException with SpongeForge)Check your server's mods folder for SpongeForge (specifically builds around 1.12.2-2838-7.2.3) or check if youMod conflictsCannot Get Config Value Before Config Is LoadedOpen the full `logs/latest.log` or crash report and look at the `at ...` stack trace lines immediately below `Mod conflictsConcurrentModificationException — two threads touched the same listA mod bug, not a setting you can changeMod conflictsCould not execute entrypoint stage 'main'The "from mod" part names the mod whose startup threwMod conflictsCrash When Opening Inventory: IllegalArgumentException: Duplicate delegatesUpdate Iris Shaders (Fabric/Quilt) or Oculus (Forge/NeoForge) to the latest release for your Minecraft version