At one of my customers we recently switched to using Microsoft Planner for basic task management and follow up of our team.
When I tried to update several tasks assigned to me I noticed an issue with posting comments:
You no longer have access to "a2e47746-ab52-4774-bba0-905b138c5c7f". Technical details
Correlation Id: 72bb4c8e-f5bb-4f8d-8e3c-03630559263e
Time Stamp: Thu, 12 Mar 2020 11:08:52 GMT
I could change other properties of the task without issues.
FIX: The issue was that my account didn’t have a subscription, more importantly I needed an Exchange Online mailbox. Once that was provisioned the issue was resolved!