To troubleshoot this issue, follow these steps.
Step 1: Make sure that you're signing in to the device correctly
The first step is to make sure that you're signing into the device correctly. For more help, go to the following Microsoft website:
Step 2: Verify the user's sign-in credentials
In addition to verifying that the user's sign-in credentials are correct, you should make sure that you enter the Session Initiation Protocol Uniform Resource Identifier (SIP URI) in the following format in both the
Account and
User Name fields. The
Account and
User Name fields must be identical.
Account: username@contoso.com
User Name: username@contoso.com
Password: ******
Note The placeholder <
username@contoso.com> represents the user's sign-in credentials.
Step 3: Check the device's firmware version
Check that the device's firmware version is at the minimum level for connection to Skype for Business Online. To view a list of supported minimum firmware revisions, go to the following Microsoft website:
Note If the user doesn’t have an Office 365 license that enables public switched telephone network (PSTN) dial-in or dial-out and intends to use the device for Voice over IP (VoIP) calls to other Lync or Skype for Business Online endpoints, the minimum firmware level across the devices should be 4.0.7577.4451.
To see what firmware version is installed on the Aastra 6725ip, HP 4120, Polycom CX600, or Polycom CX3000, select
Menu on the Home screen, and then select
System Information. For the Polycom CX700, tap
Advanced on the Home screen, and then tap
System Information. You may have to scroll down to see the
Version field.
If your device doesn't have the minimum version installed, you must upgrade your device. If you have access to a Lync on-premises environment that's configured for device updates, you can update the device by signing in to the on-premises environment. If you don't have a Lync on-premises environment, you must contact the manufacturer of your phone.
Step 4: Verify that there is no authentication proxy
Lync Phone Edition devices don't support authentication proxies between the device and the Skype for Business Online endpoint. Contact your IT department to see whether the network requires an authentication proxy.