Cause—On Forefront UAG activation, a timeout occurred and the Teredo interface could not be enabled. Warning: Serious problems may occur if you modify the registry incorrectly using the Registry Editor or another method. These problems may require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
Solution 1— Ensure that IPv6 components are fully enabled as follows:
Solution 2— Manually change the Teredo state to online as follows: