Call forwarding and voice mail not working for LBR users who're signed out of all clients in Skype for Business Server 2019 and 2015

Symptoms

In a Microsoft Skype for Business Server 2019 or Skype for Business Server 2015 environment, consider the following scenarios after you configure User A for Location-Based Routing (LBR):

      

Scenario 1:
      

• User A signs out of all clients.
• User B makes an inbound PSTN call to User A.

      

Scenario 2:
      

• User A sets up call forwarding to send all calls to voice mail.
• User A then signs out of all clients.

      

Scenario 3:
      

• User A sets up call forwarding to an external mobile phone number.
• User A then signs out of all clients.

      

In all scenarios, an inbound call will hear a fast busy. The caller isn't routed to voice mail or not forwarded to the external number.

Resolution

To fix this issue, install one of the following updates:

• For Skype for Business Server 2019, install the December 2019 cumulative update 7.0.2046.151 for Skype for Business Server 2019, Front End Server and Edge Server.
• For Skype for Business Server 2015, install the May 2020 cumulative update 6.0.9319.580 for Skype for Business Server 2015, Front End Server and Edge Server.