Horrible odor coming from sink

[Willi49]

The sink in my bathroom has a sewer type odor that comes from the drain. It's not constant, usually in the evening and more so on warmer days. I have tried cleaning it with vinegar & baking soda or bleach, but that only works temporarily. The drain is not slow so I don't think there is any type of clog. I live in a condo so I am not sure if this is an inside problem in which I would need to call a plumber or if it is something outside of my walls in which the HOA would use their plumber. The sink is against a wall shared with another unit. I don't trust the management company that our HOA has so I was just wondering if anyone had any idea what the problem might be before I try calling them.

 

[Matt30]

See if there's anything stuck in the p-trap, something could be laying in there rotting. Also fill up the sink and run some clean water down the overflow. That's a great spot for bacteria to hide and soap scum and whatever else can collect and make an odor. You can also by foaming drain cleaners that are made to expand in these places and eliminate stink.