Tracking, updating, and organizing tasks within Microsoft Teams or integrated apps
It appears that premium capabilities are currently not available for customers in Government Cloud Communities (GCC) High nor Department of Defense (DoD) tenants. This limitation may be affecting the synchronization between planners for project management and the assigned member's "My Day" task planner. Unfortunately, if you are using a government premium license, there may not be a workaround to enable this feature due to the restrictions in place for those environments.
You might want to check if there are any updates or changes in your organization's Microsoft 365 roadmap or reach out to your IT administrator for further assistance regarding this issue.
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