External users connect to meetings ok with desktop client but unable to connect with Windows web app RRS feed

  • Question

  • Hello, having an issue where our external users or guests are unable to connect to a meeting using the Skype Meeting Windows web app.  Users are unable to connect using the web app whether as guests or signed in users.

    When users attempt use the desktop app on the same external computer, it connects fine with no issues.

    Also, if you connect that same computer to the internal network, the web app connects fine.

    The symptoms of the issue with the web app are, it downloads and installs fine for the user, then launches fine when you click on a meeting URL, then the user is presented with the option of joining the meeting as a guest or signed in user.  From there after they click "Join" it just sits there with the message:  "Have a good meeting.  We're connecting you..."  It sits there for a couple min at that screen then eventually the app just closes on its own.

    Another issue, that I'm wondering if it's related, is when attempting to use the Skype for Business mobile app, you can log in fine, but after logging in you get a spinning Connecting... message and a message above that that says: "Failed to Process the server response. Please try again.  If the problem persists, contact your support team."

    At one point after I built this Edge environment a few years ago, these features used to work, and other than Skype for Business server upgrades, certificate updates and a backend database move, the only other changes that could have possibly occurred over this time period would be on our network and proxy side.

    I've also gone through this document with a fine tooth comb to make sure at least that the areas of our environment that I have access to (DNS, Certificates, Server Configuration) are configured properly:


    I anticipate having to work with my network/proxy server team to troubleshoot this, but wonder where the best places to look for this issue based on the consistent and specific issues.

    Thank you for any assistance you may provide.

    Saturday, August 24, 2019 1:05 AM


All replies

  • Hi Joe111122311344,

    The following image describes the workflow of Lync Web App Client:


    Whether internal or external Lync Web App client, both will access UCWA. So, you can check UCWA.

    Lync web app client access services via Reverse Proxy Server and Edge Server.

    Make sure the required ports of Edge server are opened on firewall.

    You can refer to https://technet.microsoft.com/en-us/library/gg425891(v=ocs.15).aspx

    Besides, you can check Lync server event if there are some errors.

    Best Regards,
    Sharon Zhao

    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Monday, August 26, 2019 8:58 AM
  • Hello Sharon Zhao, thank you for your answer, that's a helpful diagram.  In our case since the Skype for Business client desktop application works fine, but the web app does not, is there a different order or workflow that the web app uses that the desktop application does not?  Such as, during the initial connection (external) does the web app interact with the proxy server in a way that the desktop application does not? (just an example)
    Monday, August 26, 2019 11:01 PM
  • Hi Joe111122311344,

    This following image shows Skype for Business Web App join process.

    1. When a client clicks the meeting URL in the meeting invite, they are connected to the Skype for Business Web Services. The Join Launcher component identifies the client type that is connecting and either launches the installed Skype for Business client or launches Skype for Business Web App.

    2. The Join Launcher connects to Skype for Business Web App and requests the conferencing URLs to be used.

    3. Skype for Business Web App communicates with UCWA to authenticate the user. This can happen over various methods, but ultimately the connecting user must be issued a web ticket to securely connect to Skype for Business Web App and UCWA.

    4. When initiated, UCWA initiates requests to the Conferencing Focus to join the user to the conference.

    5. The user is placed in the meeting lobby and joins when admitted.

    6. Going forward, all communications with the Conferencing Focus happen through UCWA. These communications include state changes for the user and the conference.

    7. The user receives conference join information in-band to connect to the A/V portions of the conference. Going forward, the browser client communicates directly with the Conferencing Server for media, or through the Edge Server if the user is remote.

    Referring to the process, I guess the issue is mostly related to Reverse Proxy server.

    I recommend that you monitor the network traffic by some tools (e.g. Fiddler, wireshark).

    Best Regards,
    Sharon Zhao

    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Wednesday, August 28, 2019 9:09 AM
  • Great, thank you for this detail, I'll run with this and I'll post if I find the fix.
    Wednesday, August 28, 2019 6:26 PM
  • Hi,

    Is there any update on this case?

    Please feel free to drop us a note if there is any update.

    Have a nice day!

    Best Regards,
    Sharon Zhao

    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Monday, September 2, 2019 1:08 AM
  • Oh just to follow up on this, the fix was related to the 3rd party reverse proxy appliance that was hosting this. Must have been an incompatibility somewhere in that product with later Skype for Business 2015 cumulative updates.  Decided to try Windows Server 2019 Web Application Proxy instead and all issues went away.  Used this article to help install the new proxy:


    Saturday, January 4, 2020 12:06 AM