Skype For Business - user cannot sign in
if the user cannot sign in to skype for business please check the following
- check the user's SIP settings with Sherif or Elie.
- go to and delete all available SIP folder for example sip_user@contoso.com
- Skype for Business 2016: %LocalAppData%\Microsoft\Office\16.0\Lync
- Finally clear SSL State
- Enjoy