1. On the Android device, go to Settings > Applications > Select the Downloaded tab at the top > Choose the Lync application in the list.
2. Tap the clear data button.
3. Relaunch the Lync application.
4. Before logging in, tap the Lync menu key and choose Options > Server Settings.
5. Uncheck the Auto-detect server option.
6. For the Internal and External discovery address, enter the following:
https://webdir.online.lync.com/Autodiscover/autodiscoverservice.svc/Root
7. Once complete, go back to the Lync sign-in screen and attempt to log in.
Reference:
Article ID: 845, Created: December 1, 2014 at 2:55 PM, Modified: August 12, 2019 at 2:30 PM