"You do not belong to a Time Approval Group with at least one active Approver."
A user may get the following message when attempting to submit a timesheet. This occurs when the system requires timesheet approvals and this user is in an approval group that does not have an approver designated.
Navigate to Admin > Setup > Approval Groups, and enter the user's last name in the Time Submitter filter to find which Approval Group he/she is in. Edit the Approval Group, click on the Approvers tab, designate an approver (by moving a manager from the left column to the right column labeled "Approvers"), then click Save. This user should now be able to submit the timesheet.
Alternatively, you can turn off the "Timesheet" property at Admin > Properties > Approval Process > Approvals > Require Approvals. However, note that this means that a submitted timesheet can move to COMPLETED or LOCKED status without an approval.