The GNSS Agency said this had led to a temporary interruption of the Galileo initial navigation and timing services. Only the Galileo Search and Rescue service was available at the moment.
Some reports had hinted that this lack of availability of the Galileo system might be due to Russian interference, and called it "a mysterious outage".
The GNSS Agency said the SAR service which is used for finding and helping people in distress was unaffected and remained operational.
"Galileo provides ‘initial services’ since December 2016. During this initial 'pilot' phase preceding the ‘full operational services’ phase, Galileo signals are used in combination with other satellite navigation systems, which allows for the detection of technical issues before the system becomes fully operational," the statement said.
"Experts are working to restore the situation as soon as possible. An Anomaly Review Board has been immediately set up to analyse the exact root cause and to implement recovery actions."