Cross platform (Unity & JS) not working

we've developed a simple game using Photon for Unity, which is working fine. We'd like to add support for cross platform HTML clients using JavaScript. Unfortunately, we can't seem to get the JavaScript clients to see the Unity ones and vice-versa.

I've gone through the matchmaking checklist:
- Both Unity and JavaScript are using the same AppID and Version
- Both are also connecting to the same master region, EU

- JavaScript clients can create a room, and that's seen by other JavaScript clients; the same happens between Unity clients
- Trying to connect from Unity into the JavaScript client's room by name yields a "Operation failed: OperationResponse 225: ReturnCode: 32760 (No match found)" warning

What could I still be missing here?