Lync 2013 - No connectivity with any of Web Conferencing Edge Servers

New Contributor


After patching Lync 2013 front end servers with March 2017 CU, I get loads of event id 41025, 41026 on FE servers. Any one else seen this and got some tips?


Connection to the Web Conferencing Edge Server has succeeded

Edge Server Machine FQDN:, Port:8057


No connectivity with any of Web Conferencing Edge Servers. External Lync clients cannot use Web Conferencing modality.

I have tested:

  • Restarted servers
  • Disabled IPv6 in registry on FE
  • EDGE responds to telnet
  • No ports blocked by firewall
  • Certificates verified (goDaddy public cert on EDGE external, internal cert on EDGE internal and FE). Internal certs from same CA, root cert is ok
  • Time out values in the Palo Alto firewall has not been verified.. in progress
6 Replies

Have the same problem for Skype for Business Server 2015 with recent updates

I found the following solution.
The .Net Framework 4.6 and 4.6.1 rollup was also installed at the same time.   


Had to add the following registry key and restart the web conferencing service.



Worked right off the bat! Great work! Thanks!
Best Response confirmed by Ivar Økseter (New Contributor)




There is a new Technet Blog article about these Issue (with workarounds):



Nice, thanks for the update.