NEW YORK — Major websites went down Thursday in what appeared to be a brief but widespread outage.

The websites of Airbnb, AT&T, Costco and Delta showed error messages around midday. They seemed to be operating normally, however, by 12:45 p.m. Eastern time.

Akamai, a major behind-the-scenes internet network company, said on Twitter during the outage that it had created a fix for the service disruption and that “based on current observations, the service is resuming normal operations.”