At this point, you should probably consult with a local tax professional since the return is way past due regardless of the tax year selected (calendar or fiscal).
See https://taxexperts.naea.org/listing/service/corporations
For an S corporation see https://www.irs.gov/instructions/i1120s#en_US_2021_publink11515kd0e416
For a C corporation see https://www.irs.gov/instructions/i1120#en_US_2021_publink11455td0e807
