The following diagnostic is generating:

For MD electronic filing, an entry is required in the "{PriorTaxYear} state tax (-1=none)" input field under Payments, Penalties and Extensions; Penalties and Interest.

Solution:

Click on diagnostic from the Diagnostics tab.

In Screen 11>Underpayment Penalty (2220)>YYYY state tax (-1=none){MD only} (code 102), enter the prior year taxes paid by the S corporation.