With the pandemic many hotels in Florida have been hard hit so I would not be surprised to see that this hotel has deflaged to save costs? It appears from the hotel's website

https://www.bluemoonhotel.com/

it is no longer associated with Marriott and if you search on Google maps it does list pricing & available to book, but only lists OTA sites to book, not Marriott...

BTW if you are needing a Marriott property nearby the winter haven autograph is a great location. Also the kimpton angler's is a nice place if prefer to be a little bit away from the center but still within easy walking distance - great hotel I personally enjoy and would recommend, but it is on different chain