Hi
Great to know that the issue has already been resolved and thanks for sharing the solution so that others experiencing the same thing can easily reference this! Since the Microsoft Q&A community has a policy that the question author cannot accept their own answer. They can only accept answers by others, I'll repost your solution in case you'd like to Accept the answer.
Issue Symptom: Teams channel is missing the email address
Resolution:
- no matter how the channel has been created from the Teams end-user interface or from the Teams admin center by an administrator the email address will be not be presented yet.
- the owner of the issued Teams group has to navigate to "Get email address" on the first place, so the task will generate the email address for the channel.
- after that the newly generated channel email address will be visible bot sites - Teams user interface and Teams Admin center.