Issue: Unable to Join Dial-in conferencing.
Recently multiple users complain that they were unable to join dial-in conferences using dial-in.
However Skype for Business client attendee were able to join but PSTN attendee were unable to join.
Follow the below steps in order to resolve issue:
1. Check services on front end server and start all Skype for Business / Lync Services related services if any service are stopped. Specially Web Conferencing, Conference Attendant etc.
2. When checked event log on front end server found multiple error/warning event logged.Event ID: 62031 and 21053.
3. Error event log show high latency issue with the file share. Then tried to access DFS path of file share. E.g. \\mydomain.com\LyncShare which path was inaccessible.
4. Then check server where file share stored which was failed to start. Corrected windows server issue and verified file share. Now able to access file share path.
5. All above error event were disappears after file share accessible.
6. Tested dial-in conferences, now able to dial conference ID and able to join the conference.
Conclusion: Dial-in conferencing were affected because file share was not availability.