Why is my cat constantly peeing by my front door, he doesn’t do it anywhere else just in that one spot

 The full text of the question:

"Why is my cat constantly peeing by my front door, he doesn’t do it anywhere else just in that one spot,we have 3 litter boxes that are cleaned daily,he’s peeing in there also but constantly by the front door (6 months old maine coon x bengal booked into be neutered on the 28th." 

The person who posted the question and who was seeking help describes inappropriate elimination ('peeing') but I don't think it is peeing. It looks more like spraying to mark territory as it occurs near the front door. This is a major point in the cat's 'home range'. The area that he considers to be his claimed territory. 

They describe their cat as a Maine Coon x Bengal cat cross. A very rare cat breed. The cat looks more like a Bengal to me. Here he is:

Why is my cat constantly peeing by my front door, he doesn’t do it anywhere else just in that one spot. This is the cat who looks more like a Bengal cat to me. Picture: u/beccamx41

If the cat feels that there is a threat outside the home and perhaps that threat is another cat (or a person) who comes into the home through the front door they might mark it to provide the strangers with a clear signal that they are stepping onto his territory.

The key is the 'front door'. Domestic cats will tend to mark territory in prominent place within their range such as on the boundaries and intersections. 

I feel that a front door might be the boundary of this cat. He might be an indoor cat. The walls and doors of the home is the boundary. 

Spraying is likely to be on the walls or door that is vertical surfaces whereas peeing will be over horizontal surfaces. That'll be the clincher. 

Check the exact location of the urine.