"This month is outside the subscription period."

Where: student profile, This month row (− / +, Back to the usual number), or Adjust the limit in the Over plan list. Owner and instructor.

Why: the month to adjust is before the start date or after the end date of the subscription.

What to do: adjust a month within the subscription period. To extend an ended subscription, the owner edits its end date (Edit on the profile) or adds a new subscription.