Is it legal to knock on the door of the property?

It is legal to knock on the door casually and ask for property fees. If many people don't pay the property fee for a long time, the property will sue the owners who didn't pay the fee, and the result of the prosecution is to make up the property fee.

Under normal circumstances, even if the property itself is not in place, in order to protect the property and prevent other communities from following suit, the law will tend to the property side. As for the place where the property is not in place, I suggest you take your camera and mobile phone to leave time and evidence for emergencies.

It is a basic contractual obligation of the owner to pay the property management fee according to the agreement, and it is a breach of contract not to pay the property management fee without sufficient defense reasons.