Why does Construct 3 Photon room reject the second player?

App ID set per project, max players cap (default 4), lobby region must match between host and joiner. Mismatched region means joiner can't see room.

Photon dashboard → Application ID. Paste into Construct 3 Photon plugin properties. Use same ID across all builds; per-environment for dev/prod.

Photon plugin Connect to region: us, eu, asia, etc. Use 'best region' for auto. Both clients must hit same Photon server.

Fix: Construct 3 Photon Room Won't Accept Second Player

Quick answer: Same App ID. Max Players > 1. Both clients connect to the same region.

Host creates room. Friend tries to join. Photon shows no rooms or rejects. Region or App ID mismatch.

The Fix

Photon plugin Properties:
  App ID:           <from Photon dashboard>
  Region:           us
  Max Players:      4

Event:
  Photon: Create room with name "test" max 4
  (other client)
  Photon: Join random room   # or by name

Same App ID + same region = both clients see the same lobby. Max Players above 1 lets the room accept multiple.

Verifying

Two clients, same App ID, same region: room joins. Different region: invisible.

“Same ID. Same region. Cap right.”

Related Issues

For mobile WebGL effects, see mobile effects. For Tap double, see tap.

Same App. Same region.