A smell is in my house

So for a couple of months a disgusting smell (similar to a fart) has been roaming my house. It's in certain places like where the bathrooms are, but it can also be in all rooms.

We already called the plumber to check for any problems. After the service, the stench was still here.

Could anyone guess or have an idea on what it is or what to do. Here are my guesses:

Sewage Human/Animal Waste