Double Vanity Sink Gurgling Issue: Double vanity sink gurgling and not draining properly. Background: I live in a town home and in our master bathroom we have double vanity sinks. A few weeks ago I noticed the right sink wasn't draining so I cleaned out the p trap. There was white gunk that was caked in there. That seemed to solve the issue. Flash forward to last week and I noticed the gurgling sound on the right side when using either left or right sink. Quick google search I deduced that it was possibly a ventilation issue causing it not to drain properly. The water eventually drains from both sink, but it's best to tackle the issue before it gets worse. The AC line also connects to the right p trap. All the other sinks and toilets throughout the house do not have trouble draining or flushing. Things I've tried: Cleaned p traps of left and right sink. Used Drano Max on both and ran hot water through it. Climbed onto roof to check vent of pipe and see if there are blockage visually and then spraying water down it. Checked AC line to make sure there are no clogs. dropped bleach pellet and ran warm water down the line. Saw water flow through line. No block. Visually inspect the pipe that connects back behind the wall, could not see any blockage. Tried to use a snake but would not bend and go in through pipe. With the left sink p trap taken out. I run hot water down the right sink and the water flows out the left pipe where the p trap is removed. I'd try to cover the pipe with my hand to let the water fill up and then move my hand and some large gunk came out. I did it 3-4 more times until there were no more debris that I could see. I've taken out the right sink p trap and put the left sink p trap back on. When I run water down the left sink, the water comes out the right sinks pipe where the trap was removed. Not as much gunk came out. https://imgur.com/hwp0Zqd Left P Trap https://imgur.com/hwp0Zqd Right P Trap Off https://imgur.com/hwp0Zqd Right P Trap On I think I've done everything I can before calling a plumber. IF there are any suggestions I would appreciate it. Thank you!