A rise in third-quarter display advertising revenue was not enough to offset a 6 percent drop in total revenue, which came in at 531.7 million.
Analysts expected $524 million in revenue, according to Thomson Reuters I/B/E/S.
AOL, which Time Warner Inc spun off after a disastrous decade-long merger, saw subscription revenue sliding 22 percent in the quarter to $192 million.
The company is trying to regain its status as one of the world's most popular online destinations that attracts online advertising dollars from the likes of auto companies and consumer packaged good makers.
AOL reported a third-quarter loss of $2.6 million, or 2 cents per share, from continuing operations, compared with a profit of $171.6 million, or $1.61 per share, a year ago.
(Reporting by Sruthi Ramakrishnan in Bangalore; Editing by Joyjeet Das)