Photon On-premises Server: operation Code: 227, return Code: 32762 (Failed to get server instance.)

Hi all, I've downloaded and followed the setup instructions for creating an on-premisis server following this tutorial: https://youtu.be/0mXmapcJ1b4 In the tutorial, we are shown how to download and setup the server, as well as what port-forwarding is required, what IP is required and we setup a simple project designed just to connect to the server we have setup. Once connected, we should load a second scene. After much effort, I cannot connect to the server that I have setup. If I run the test app on the PC where the server is running, it cannot connect to the server at all and I get the text on screen "Peer Created" as well as the warning: "TimeoutDisconnect while connecting to: MYPUBLICIPADDRESS. Check if the server is available.". If I run the same app on another pc, I manage to connect and load the second scene as it should do, but then I get the error: "operation Code: 227, return Code: 32762 (Failed to get server instance.)". If I run the testclient for LoadBalencing, I get the error: "OnOperationReturn: CreateGame failed: ReturnCode: 32762 (Failed to get server instance.)". Does anyone have any suggestions on how to fix or debug this issue?