If you are in the dark and your cape portal is not lighting up, work through these checks in order.
Check the basics
1. Is it a movie cape? The pack only makes the portal shapes on movie capes glow. Other capes are meant to look the same as before.
2. Is your cape showing at all? Open Options → Skin Customization and set Cape to ON.
3. Is the pack active? Open Options → Resource Packs and confirm Emissive Cape Portals is in the Selected list, not the Available list.
4. Is it really dark? Torches, lanterns, and daylight can hide the effect. Test in an unlit cave or at night.
Check for conflicts
- Pack order: In the Selected list, packs higher up take priority. If another resource pack also changes shaders or cape rendering, move Emissive Cape Portals above it, click Done, and test again.
- Shader loaders: This is a core shader, so it does not need Iris or OptiFine. If you use one of those mods and have a shader pack switched on, it may replace the vanilla rendering this pack relies on. Turn the shader pack off from the loader's shader menu and test again.
- Reload: Press F3 + T to reload resource packs, or restart the game after making changes.
If the glow appears with every other pack removed, add your other packs back one at a time to find the one causing the conflict.