The problem is that the GST registration number on the receipt does not include the RT0001 portion. If I add those 6 characters to the number, it is accepted, but is it really now a valid number? What does RT0001 mean? Would adding "AB9999" at the end also be a valid number?
I did go to a GST number registration validation site, entered my motel's 9 digit number and it was identified as a valid number and identified the motel by name. There seems to be a disconnect between what CRA expects as a GST number and what companies are printing on their receipts.
By the way, I added the RTOOO1 to the GST number on the Ontario staycation entry form and it was accepted.