Unable to connect, as no valid crossdomain policy was found


Our game has suddenly had some connection problems. It doesn't completely fail to connect. Our program has a 30% connection success rate. When it fails it says this in the console:
Connect() failed: System.Security.SecurityException: Unable to connect, as no valid crossdomain policy was found
at System.Net.Sockets.Socket.Connect_internal (IntPtr sock, System.Net.SocketAddress sa, System.Int32& error, Boolean requireSocketPolicyFile) [0x00000] in <filename unknown>:0
at System.Net.Sockets.Socket.Connect (System.Net.EndPoint remoteEP, Boolean requireSocketPolicy) [0x00000] in <filename unknown>:0
at System.Net.Sockets.Socket.Connect (System.Net.EndPoint remoteEP) [0x00000] in <filename unknown>:0
at System.Net.Sockets.Socket.Connect (System.Net.IPAddress address, Int32 port) [0x00000] in <filename unknown>:0
at ExitGames.Client.Photon.NConnect.StartConnection () [0x00000] in <filename unknown>:0
PhotonHandler:DebugReturn(DebugLevel, String) (at Assets/Photon Unity Networking/Plugins/PhotonNetwork/PhotonHandler.cs:158)
NetworkingPeer:DebugReturn(DebugLevel, String) (at Assets/Photon Unity Networking/Plugins/PhotonNetwork/NetworkingPeer.cs:746)
ExitGames.Client.Photon.EnetPeer:Connect(String, String, Byte)
ExitGames.Client.Photon.PhotonPeer:Connect(String, String)
NetworkingPeer:Connect(String, String) (at Assets/Photon Unity Networking/Plugins/PhotonNetwork/NetworkingPeer.cs:182)
NetworkingPeer:OnStatusChanged(StatusCode) (at Assets/Photon Unity Networking/Plugins/PhotonNetwork/NetworkingPeer.cs:1157)
PhotonHandler:Update() (at Assets/Photon Unity Networking/Plugins/PhotonNetwork/PhotonHandler.cs:65)

We just subscribed to the 100 ccu cloud account option a week ago. Everything was working great last week and then it started doing this again (its done it before on the 10 ccu account). We are really going to depend on this software to work. Everything we've worked on in the last 8 months would be destroyed if we cannot get Photon to cooperate.


  • I can't reproduce the issue at the moment, so maybe it is related to some of the server trouble we had last week.

    a) Please verify if it's working now.
    b) Let us know which server region you use and when exactly this happened.

    I will ask my colleagues if this relates to some known update/rollback or issue.
  • Hi Tobias,

    I'm still getting this issue with the report back from the unity console that this is a cross domain policy issue. We were having no problems for the about 8 days ago then all of a sudden this started happening again. We first thought it might be due to the fact we were using the free 10 ccu cloud account and they were low quality servers or something. Our cloud region is US.

    This seems to happen at random. About 2 out of 3 rooms fail to make. But it seems after a room has been made its pretty stable. We've played for half an hour on one server room just fine while this instability is happening elsewhere.

    Do you have an email support line?
  • Support mail address is: [email protected]
    I pointed my colleagues to this topic already, so unless you need to share private stuff, this thread is fine to discuss.
  • Hello,

    upon investigation, we found that we indeed hat an issue with Policy files on one of our US server in the last days. If you were randomly assigned to that one server, you might have encountered the issue several times in a row, while it worked for players on other servers.

    The machine is now fixed, we apologize for the inconvenience. Let us know if we can assist with anything else.