The penalty [for failure to timely file] is $205 for each month or part of a month (for a maximum of 12 months) the failure continues, multiplied by the total number of persons who were partners in the partnership during any part of the partnership's tax year for which the return is due.
See page 5 https://www.irs.gov/pub/irs-prior/i1065--2019.pdf
In an effort to get the penalty waived, you have the option of sending an explanation to the IRS which will determine if your explanation meets reasonable-cause criteria.
See https://www.irs.gov/pub/irs-utl/36-Responding%20to%20IRS%20Proposed%20Penalties.pdf AND
https://www.irs.gov/businesses/small-businesses-self-employed/penalty-relief-due-to-reasonable-cause
