Start with the right checks.
A lobby wait is different from an account restriction. The message on screen is the best starting point.
What to do next.
Open the original invitation and confirm the meeting time and link.
Check which account is signed in. Use the account the invitation was sent to when the meeting requires it.
If you are in the lobby, ask the organizer to admit you. If the meeting is locked, only the organizer can resolve that.
On a phone, use the Teams mobile app. On a computer, use a supported browser or the Teams app. Note the exact error if joining is still blocked.
Check the result.
You reach the intended meeting and can see or hear the participants. Verify the meeting identity before sharing information.
Stop and get help if…
The message mentions organizational policy or an unexpected account verification request. The organizer or company administrator may need to act.