Unable to sign in Skype for business after password reset.

1. Kill Skype for Business with the task Manager
2. In the folder C:\Users\**username to replace**\AppData\Local\Microsoft\Office\16.0\Lync, delete the subfolder with the email address.
3. In the folder C:\Users\**username to replace**\AppData\Local\Microsoft\Office\16.0\Lync\Tracing delete all files (don’t delete the folder itself)
4. Flush the DNS in a shell with ipconfig /flushdns.
5. Restart Skype for Business.

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