Microsoft project management software used to plan, manage, and communicate a project schedule and other information among workgroup members, project managers, and other stakeholders.
Dear Yennyfer Perozo,
Good day! Thank you for posting to Microsoft Community. We are happy to help you
Based on your description, we understand that you can't create a task in Planner.
Based on my investigation of the error information you provided, try the steps in this document first to see if they can help you:
Manage who can create Microsoft 365 Groups | Microsoft Learn
We look forward to your reply. Thanks for your cooperation.
Sincerely,
Tin | Microsoft Community Moderator