Skype for Business "You've left the call" Can't join meetings. RRS feed

  • Question

  • Hello,

    We are using Skype for Business 2016 MSO (16.0.4849.1000) 32-bit

    Whenever I try to join a meeting set up in skype for business (all internal business contacts), it attempts to connect me but then fails and says "You've left the call". When I try and use the web app, it says "You're unable to join the meeting. This could be due to your network configuration...". However, I am able to make single calls to people inside my organization successfully. 

    Am I able to send Skype for Business through a proxy? I've checked of our proxy settings and all the correct links are permitted. Are there special firewall settings I need to allow in order for Skype for Business meetings to connect?

    Thank you.

    Thursday, August 8, 2019 7:31 PM


  • Hi Periphery87,

    If you bypass the Proxy, could it work successfully?

    If it works, the issue may be related to Proxy server configuration.

    Please make sure it allows UDP traffic.

    In my research, I found a related article about certificate requirement (OCSP/CRL check) for Proxy server, you could have a look at:


    In addition, when it comes to Skype for Business traffic over proxies, it is recommended to bypass proxies.

    Note: This response contains a reference to a third party World Wide Web site. Microsoft can make no representation concerning the content of these sites. Microsoft is providing this information only as a convenience to you: this is to inform you that Microsoft has not tested any software or information found on these sites and therefore cannot make any representations regarding the quality, safety, or suitability of any software or information found there. There are inherent dangers in the use of any software found on the Internet, and Microsoft cautions you to make sure that you completely understand the risk before retrieving any software on the Internet.

    Best Regards,
    Shaw Lu

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

    • Marked as answer by Periphery87 Friday, August 9, 2019 1:39 PM
    Friday, August 9, 2019 6:31 AM