Apparently, someone, probably you or another in your household, requested a letter from the IRS verifying that you did not file a tax return for 2019. The IRS responded stating that as of Nov 11, 2019 they have no record of a tax return. That's it. Nothing more. Nothing less.
Since the IRS is months behind in processing returns, it would seem apparent to me that they just haven't gotten to your 2019 tax return yet, is all. Therefore, as of Nov 11th they have no record. That does not mean they did not receive your mailed tax return. It only indicates that they haven't gotten to it and processed it yet as of the date stated in the letter.
