Fix Microsoft Lync for Mac OS X Login Fail Error

I’m working for startup in the consumer financial space. We use Office365 at work for emails, calendars, and literally everything else. Being an OS X user, the problem I had was configuring Lync. I keep switching between a PC at work, Mac at home, Android in between. Lync seamlessly works with PC, and Android without any out of the box configuration, but as odd as it may sound, Lync for Mac just won’t login – “Sign in to Microsoft Lync failed because the service is not available or you may not be connected to the internet.”

Even after lurking around Technet and other Microsoft support forums, I failed to get it running. Folks at Technet suggested that it could be an issue with Root Certificate. I tried downloading the root certificate from the certmgr.msc and plugging it into Keychain Access, I also tried disabling OS X firewall, but that didn’t work either.

Turns out, Microsoft Lync for Mac  simply does not work out of the box, and you need to change both the Internal Server Name and External Server Name for it work.

Hopefully, this post will help somebody out there to get Microsoft Lync running on OS X without any struggle. Read on:

Open Lync (Application > Lync), and click on “Advanced” with a little gear icon next to it.

Check the Manual Configuration Checkbox and use these settings:

Internal Server Name:

Externam Server Name:

That’s it. Try logging in with your Office 365 credentials and it should work.

This post was published by on July 27, 2012

About the Author: Thilak Rao works as a Social Media Expert. He is one of the first professional bloggers from India, and he loves to write, travel and click photos. Follow him on Twitter @thilak

  • Mike

    Thank you thank you thank you… Saved me a few hours!!!

  • Thilak Rao

    I’m glad I was of help!