Additional features, settings, or issues not covered by specific Microsoft Teams categories
Hello Miguel Gonzalez Vigil,
Thanks for your post here.
From your description, you cannot access Planner as a guest in an organization. Given this situation, I suggest you go to Teams Web App and check it you receive the same error. It can help us determine whether it only happened on Teams client.
Besides, you can also try clicking the Planner tab and selecting Go to website button at the upper-right corner and see if you can access it.
To better help you with your problem, please provide the following information to me:
1. Please check if other guests in this organization have the same error.
2. Try to sign out and sign in again to see if you still have the same error.
3. How long the problem lasts?
4. Whether the same issue occurs when you access Planner tab in other teams?
Thanks for your time.
Regards,
Seven