Meaning:
Lit. “to kiss the doorknob”. This is used to say that someone tried to meet a person or enter a building in order to buy something, get some information or, say, attend a concert, but wasn’t let in or the person she/he wanted to meet wasn’t there.
The expression itself is fairly neutral, not necessarily suggesting bad intentions of the hosting party, but is quite often used to say that, for instance, the manager actually was at the office,but simply did not want to talk to an employee and instructed her/his secretary to say she/he’s out.