LONDON (AP) — London’s transit authority said Monday it is not renewing Uber’s license to operate in the British capital, dealing a major setback to the ride-hailing company.

Uber vowed to appeal the decision and has 21 days to do so. The company can continue operating while the appeals process is under way.

Transport for London cited “several breaches that placed passengers and their safety at risk” in its decision not to extend Uber’s license, which expires at midnight Monday.

The transit authority said that despite addressing some issues, it “does not have confidence that similar issues will not reoccur in the future.”

As a result, Transport for London has deemed Uber “not fit and proper at this time.”

Uber said in a statement that the decision not to renew its London license “is extraordinary and wrong.”

“We have fundamentally changed our business over the last two years and are setting the standard on safety,” Uber said, noting that Transport for London had found the company to be fit and proper operator two months ago.

Transport for London had already been keeping Uber on an increasingly tight leash. It had renewed Uber’s license for only two months in September and imposed stricter conditions following concerns about aggressive corporate tactics and passenger safety.

The transit authority said one of the key issues behind its decision was a change to Uber’s systems that allowed unauthorized drivers to upload their photos to other driver accounts.

This let them pick up passengers as though they were the booked Uber driver on at least 14,000 trips, which means all those journeys were uninsured, Transport for London said.

Some passengers also traveled with unlicensed drivers, including one whose license was previously revoked by Transport for London.