On August 22, a Soyuz ST rocket lifted off with the first two satellites in the Galileo constellation. The liftoff and initial part of the mission proceeded successfully, which led to the release of the satellites according to the planned timetable. Nonetheless, after the separation of the satellites, the data provided by the telemetry stations, operated by the European Space Agency (ESA) and the French space agency (CNES), indicated that the satellites were not in the expected orbit.
The intended orbit for these two satellites was circular, inclined at 55 degrees with a semi major axis of 29,900 km. However, the satellites are in an elliptical orbit, with excentricity of 0.23, a semi major axis of 26,200 km and inclined at 49.8 degrees.
According to preliminary analyses, an anomaly is thought to have occurred during the flight phase involving the Fregat upper stage, causing the satellites to be injected into a noncompliant orbit.
The official press release by Arianespace can be found here.