Lync 2010/2013 stores credentials when you initially set it up. This might lead to connection issues after resetting password.
Here are the steps to fix the issue (close Lync first):
Remove the certificate
- Go to Internet Explorer > Tools > Internet Options > Content > Certificates
- Remove the certificate issued by Communication Server under Personal > Certificates
Clear entries in Credential Manager
- Go to Start > Control Panel > Credential Manager > Windows Credentials > Generic Credentials
- Remove the entry with the following address: Microsoft_OC1:firstname.lastname@example.org:specific:*
Remove Crypto folder
- Go to %System_Drive%\ProgramData\Microsoft\Crypto\RSA
- Remove the folder S-1-5-*
Set the Communicator registry key to disable saving password
- Go to Registry Editor (Start > Run > regedit > OK)
- Choose HKEY_CURRENT_USER\Software\Microsoft\Communicator
- Double-click the value SavePassword and set it to 0
After following all the steps run Lync again and enter correct credentials.