I have configured My Sites in SharePoint 2013.  However, when I attempt to refresh the tasks list it fails with the following message:

Sorry, we’re having trouble refreshing your tasks.Contact your administrator if you continue to have problems.

We are having trouble refreshing your task

The fix for this is quite simple:

1. Log in to Central Administration

2. On the Application Management page, under the Service Applications section, click Manage service applications

3. Highlight the User Profile Service Application and click the Permissions button in the ribbon

4. Add the service account that is configured to run the Work Management Service Application and grant Full Control.

5. Click OK

Now the task lists refreshes without error.