If you are receiving Failure to File notices, you likely still have an active retail license for the rental accommodations.
OTCs report Sales and Accommodations Taxes to the state using their own retail license. They will not file using the retail license of the property owner whose accommodations they are renting.
If you have an active retail license, you must file Sales and Accommodations Tax returns for each filing period to avoid receiving Failure to File notices. For any filing periods when all of your rentals were through an OTC, file your returns with all zeros.