You may have encountered negative values in the dashboard and/or a negative value when you're setting a up a new schedule in the deposit section:
This occurs when your token/gas balances dip below what is needed to automate your schedules. This can be triggered by the user when they withdraw token/gas balances that are still needed by a schedule. Or when gas prices spike significantly.
You may resolve this by depositing more token/gas to allow for schedules to continue.