Chances are that the sink drain is clogged before the clean out. The small homeowner snakes are not large enough to remove badly clogged drain, often they just make the clog tighter. It is likely that debris, perhaps sheet rock mud, got into the drain during the remodel. At any rate, you need plumber with professional drain cleaning equiment to clear the clog. Don't try dumping chemicals in there, it won't clear the clog and will produce a hazard for the plumber.