That is still your property and responsibility. Find the clean out and rent an electric auger with a 2" cutter head. Could be 200" so rent plenty of snake, got any trees along the way? That or call a plumbing or sewer contractor

Follow the excellent advice giver by Bob and locate your house cleanout. Typically house cleanouts are located not over 18" off the foundation and brought up to grade.
Over the years dirt and soil can build up over the clean out but we take a pointed rod and go poking around until we find it. Once found run your snake all the way out to the street. Good luck, Tom