Frankfurt Airport is now entirely closed for arrivals.
Lufthansa said construction work on a rail line in Frankfurt was to blame for the massive IT failure. Currently, the breakdown is presumed to have been caused by a cable getting slit during rail construction work on the Frankfurt S-Bahn. Deutsche Bahn stated it immediately informed Telekom about the damage and apologized to affected travelers for the inconvenience caused.
Lufthansa cited a statement by Telekom saying that the complete fixing of the cable disruptions would likely take until Wednesday afternoon.
Flights are still being allowed to depart Frankfurt Airport, though these are exclusively non-Lufthansa Group flights.