Troubleshooting Skype for Business (ex Lync) login issues

Skype for Business (which was previously called Lync) is a nice instant messaging (IM) and conferencing application for business use. I'm happily using Skype for many different needs, but sometimes, I might have trouble logging in. Last time this happened when working from a hotel abroad.

When Skype for Business logs in and there are issues with the login, you might or might not get useful error messages. Sometimes, the user interface just stalls, and nothing happens. I'm currently using Skype for Business through Office 365, and this makes it slightly more complex to do troubleshooting.

Luckily, Skype counts good logging support which you can enable. Once you have enable full logging (through Tools/Options, and then General, and the option "Logging in Skype for Business"), Skype collects status information to a text file under the current user's profile.

More specifically, the logs are collected to the folder "C:\Users\my.name\AppData\Local\Microsoft\Office\15.0\Lync\Tracing". In this folder, there can be dozens of files, but a file named "Lync-UccApi-0.UccApilog" is the more detailed. This is a text file that collect lots of information about the current connection and attempts to connect.

Hope this helps!