Getting error message 32752 when creating a room

Hello,

I'm working on a multiplayer game in Unity, using Photon PUN 2.39.

Starting with today, sometimes when I want to create a room the OnCreateRoomFailed callback is triggered with 32752 return code and the following message:

There was no recent update to the game (I tested even with a stable one-year-old version that is working for a while) so this error is appearing out of nowhere.

The code for creating a room is this:

private static readonly RoomOptions RoomOptions = new RoomOptions
{
    MaxPlayers = 20, CleanupCacheOnLeave = false, PlayerTtl = 0, IsVisible = true,
    CustomRoomPropertiesForLobby = new[] {Constants.MapNameProperty}
};

public void CreateRoom(string roomName)
{
    menuManager.SetInfoText("Creating a room...");

    PhotonNetwork.CreateRoom(roomName, RoomOptions);
}

I'm also using webhooks but they are all quite simple. For example, the server code (nodejs express) for the endpoint connected to PathCreate is something like this:

router.post('/createAction', (req, res) => {

    // save data about the room

    return res.json({
        ResponseCode: 0
    });
})

and it's working for a year without a problem.

Disabling webhooks seems to solve the room creation problem.

What do you think is the problem and how can I solve it?