Doing some “sniffing”, looks like Lync is sending a Culture ID that the server doesn’t recognize and replies with a “401 Bad request” in my case en-CH doesn’t exist:One workaround do far seems to be: define a language that exists on the region with so Lync can send a valid culture ID.
Tkmikal found this Microsoft KB3096704 recognizing the issue:
“This problem is fixed in the Microsoft Skype for Business for iOS app that will replace Lync for iPhone and Lync for iPad when it’s released. No fix for this issue is scheduled for the current releases of Lync for iPhone and Lync for iPad”.
This should stay by here, but then I went “under” the iOS and found an additional cause. If you have the location services disabled during the iOS process update, it will not be able to set all the new information parameters about language and region for version 9.
So, here’s a stable solution:
- Turn on Location Services on the iOS device, and be sure to have an internet connection active;
- Switch the language to another one and back to the one you want – this is a fast way to make the iOS download all the iOS9 configuration format;
- Start Lync and you are now able to sign-in;
- You can now disable back the location services. Lync will still sign-in correctly because iOS9 language settings are now installed.