LONDON — Yikes, talk about a PR nightmare.

Ryanair has apologized after customers who received compensation for cancelled flights complained that the checks bounced.

Europe’s largest discount airline says “a tiny number” of checks were issued without a signature because of an administrative error. Ryanair says new checks have been sent to customers along with a letter of explanation.

According to the airline, the problem involved 190 compensation checks out of some 20,000 issued in July. The company says “we apologize sincerely for this inconvenience, which arose out of our desire to issue these compensation checks quickly to our customers.”

Ryanair cancelled hundreds of flights last year due to problems with pilot scheduling, and strikes have led to more cancellations this summer. European Union rules require compensation for cancelled flights unless cancellations result from issues outside the airline’s control.