You can verify the Teredo state by using the following command:
Netsh Int Teredo Show Stat
If the state is in dormant or qualified that means it is working.
If the state is in offline you need to troubleshoot the issue. As you can see in the above screenshot, State is in offline and the reason is client is in a managed network. Which means Teredo has detected that you are inside a corporate network. In this case you need to change the Teredo type to enterpriseclient to resolve the issue.
You can you the following command:
Netsh Int Teredo Set State Enterpriseclient
You have the following Teredo types available:
Enterpriseclient -> Skip managed network detection
Server -> Enable the Teredo server
Client -> Enable the Teredo client
Disabled -> Disable the Teredo service
The default state is client. Also, you can disable Teredo by using the following command:
Netsh Int Teredo Set State Disabled