The Third Authority.

The Celestial Supreme refused to accept the backstabbing betrayal of their entire race. He pointed his hand at the swirling portal and he ordered with the full power of his Authority as the Celestial Supreme. "FREEZE."

Even if a channel is opened, it can still be closed. If a Celestial Authority opened it, another one can close it. Two Authorities were used to open the channel, he has two Authorities too. One as the god of order and another one has the Celestial Supreme, so the portal will close with his command.