Airline company IndiGo on Monday faced server problems across its network in the country, leading to long queues of frustrated passengers at airports. The reason for the disrupted servers was not immediately clear.

“Our systems are down across the network,” the airline tweeted. “We are expecting the counters to be crowded more than usual. Please bear with us as we try to solve the issue as soon as possible.”

An unidentified IndiGo representative told The Indian Express in the morning that servers in Gurugram, Chennai, and Pune were facing the problem, and said that it would take about an hour to resolve it. “We are helping the customers through phone, only this particular software is down, the customers can still carry out their ticket booking process through our website,” he said.

Another unidentified official with the airline at Kochi airport in Kerala said flights had operated according to schedule till 9.40 am on Monday, but the systems then went down.

An afternoon flight to Chennai from Kannur had been delayed for 15 minutes, an IndiGo official at Kannur in Kerala said.

Flights within Karnataka from Bengaluru to Mangalore had been cancelled along with one from Bengaluru to Chennai in Tamil Nadu. At least nine flights had been postponed in Mumbai, the airline said.

“We regret the inconvenience caused to all our passengers,” IndiGo said, according to India Today. “While we are proactively informing them about the situation, for assistance, we request all passengers to contact us on our social media handles or reach out to our customer care.”