If your teacher notifies you that you are participating in the lesson as an external user, you are logged in with a different M365 account than your Semper account. This can be your private account, a professional account, an account from another school or from another user on your computer. You will then have to switch between these accounts. How you do this depends on how you attend the meeting:
The easiest way is to use a separate browser for your Semper account.
If you cannot install another browser, you can surf to Moodle in a private window or incognito mode. How you do this exactly depends on your browser.
You can add more than one account to the Teams app. Then you can easily switch between the different accounts.