Late Filing of GSTR 3B for Nil Return

Our GST Registration got cancelled in Nov after a SCN due to which the option to file return for GSTR-1 and 3B was not available online. Now after department inquiry the registration has been restored and now we are filing the return for both Nov'20 and Dec'20 in Feb'21. 

What will be the interest or penalty for late filing of GSTR-3B where we do not have any tax liability to pay as there is only ITC credit in the return and no output liability.