My first floor bathroom sink drain is clogged. When I remove the sink and trap from the wall the water drains. When I reconnect the sink and trap to the wall, the sink won't drain. Other house drains function normally. There is no odor coming from any drains. The drain pipe going down from the bathroom appears to be unclogged. Where should I look next?

If you have a clogged vent you will hear a gugle as the drainage attempts to vent through a trap.

When I remove the sink and trap from the wall the water drains. When I reconnect the sink and trap to the wall, the sink won't drain.
Please explain how you get water to drain with the sink and trap removed. Back to you, Tom

When you hear hoffs think horses not zebras. You most likely have a clogged drian. Have you tried to rod that line going into the wall?