The tasks link from the menu on the left in my project site shows an error

Unable to access a planner task from the SharePoint Online page:

Something went wrong

If the problem persists, contact the site administrator and give them the information in Technical Details.

TECHNICAL DETAILS

ERROR:
This plan has been deleted. Contact the plan owner.

groupId=4f06325d-9f24-45cf-b31a-a305ee51164a&planId=gldsg9zbF0aDcp0jKvApP5cADIFY

I checked the group in the azure ad and it's not deleted it present there.