Connect Tasks with Outlook

Hi, When users try to connect a task list to their Outlook they get the below error message:

We weren't able to start syncing your tasks because one or more pre-requisites for connecting to Exchange server could not be found. Please contact your administrator to resolve this issue.

I think this error may have started occuring since I set the Work management Service up to aggregate tasks in staff My Sites.

We do not use Exchange 2013, we use Exchange 2010 and Office 2010.

Thanks