UPDATED. ILS has announced that the launch of the Proton launch vehicle with the SES-5 satellite has been postponed for technical reasons related to the Proton launch vehicle.
The launch date will be determined at a later time. ILS first said there would be a 24-hour postponement of the launch, but later issued a statement that a new launch date would be announced at a later time.
On June 18, Khrunichev engineers at the launch site received an out of tolerance telemetry reading on a first stage subsystem during pre-flight testing. However, based on additional pre-flight testing performed on June 19, it was determined that further investigation is necessary, requiring the launch vehicle be returned to the processing hall for additional testing.
The vehicle and satellite remain in a safe configuration at the launch site.