Massive flight delays and interruptions have been caused by an IT issue at Germany's flag carrier Lufthansa, the business said on Wednesday. It added that the reason of the issue is yet unknown. According to the airline on Wednesday, "an IT failure at Germany's flagship carrier Lufthansa has caused huge flight delays and disruption at airlines throughout the group worldwide." The reason of the IT error is yet unknown, the business added. A Lufthansa official told Reuters that "there is a group-wide IT system outage." Numerous German airports' photos and videos depicted turmoil as thousands of stranded travellers waited to be checked in. At 0936 GMT, Lufthansa shares were down 1.2%. Lufthansa also owns SWISS, Austrian Airlines, Brussels Airlines, and Eurowings. Intense efforts were being made by Lufthansa to the issue, according to a corporate representative quoted in Bild. On social media, travellers said that the company's breakdown had forced them to board aircraft using pen and paper and that they were unable to process bags digitally. The Lufthansa Group's airlines are now experiencing an IT outage, according to a tweet from Lufthansa. Flight cancellations and delays are a result of this. "We apologise for the trouble this is giving our customers." Two days prior to scheduled strikes at seven German airports that are anticipated to cause significant delays, there was an IT system failure.