BlackBerry users in North America faced delays in receiving e-mail on their devices Thursday.
The company that makes the popular messaging phones, Research In Motion Ltd., later said technicians isolated and resolved the issue. The company said it is investigating the cause.
RIM said users were still able to make phone calls, browse the Internet and send and receive text messages. RIM didn't say how many users were affected or how long the outage lasted.
RIM's system is relatively reliable, but its centralized structure means that any problems can affect millions of users.
In February 2008, an upgrade to the wireless system apparently caused a three-hour service disruption. In April 2008, a minor software upgrade crashed the system. A software glitch also caused a smaller disruption in September 2008.
After initially focusing on corporate customers, RIM has expanded its reach into the consumer market in recent years. The devices face increasing competition from devices such as Apple's iPhone, Palm's Pre and the Motorola Droid.
The outage came the same day RIM, which is based in Waterloo, Ontario, was to release quarterly earnings.