Fixing Elytra Flight That Stops Working After Installing Caelus API

If your elytra suddenly refuses to deploy after adding Caelus API, the cause is almost always a conflict or a missing dependency, not the library itself. Caelus changes how vanilla elytra checks for flight permission, so anything that also touches elytra behavior can clash.

Work Through the Likely Causes

First, confirm your loader matches the Caelus build you installed. A Forge build will not run on NeoForge and vice versa, and a mismatch often shows up as elytra simply not working rather than a clean crash. Second, check whether another mod in your pack also modifies elytra flight, such as a flight overhaul or an armor overhaul. Two mods fighting over the same behavior is the most common real cause.

Test in a Clean Setup

Create a fresh test world with only Caelus and the mod you suspect. Try to glide with a vanilla elytra. If it works there but not in your full pack, add mods back in small groups until gliding breaks again. That isolates the conflicting mod quickly.

Check the Attribute, Not the Item

Remember that flight is now gated by an attribute rather than being hardcoded to the elytra item. If a mod strips or overrides attributes on your player, it can silently set your flight permission to zero. Removing that mod, or checking its config for attribute-related options, usually restores gliding.