Uber may not be allowed to operate in London in the future after its license renewal request was denied on Friday. The company’s license to operate in the British capital expires on Sept. 30. The company has called for talks with London’s transport regulator Transport for London to find a solution to the matter.

Uber CEO Dara Khosrowshahi said in an open letter to the city, “We will appeal the decision on behalf of millions of Londoners, but we do so with the knowledge that we must also change.” In the letter, Khosrowshahi promised to be more responsive to London’s concerns. Those concerns include the way it conducts background checks on drivers and how the company reports serious incidents to the police.

Last August, Head of the Metropolitan Police’s taxi and private hire unit Inspector Neil Billany alleged the company was putting its customers at risk by turning a blind eye to criminal activity by its drivers. Billany claimed the company was “deciding what to report” based on what was “less damaging to its reputation.”

Uber’s Head of Cities for the UK Fred Jones defended Uber’s record for dealing criminal incidents. Jones said the Met Police Force had not spoken the company directly before taking its concerns public. He also maintains that the TfL had not been clear about it concerns. Jones said, “Once we understand them, we can work with them to figure out what is it that they would like us to do and how can we move forward and I think that’s the important next step.”

On Friday, Uber released a statement accusing the TfL and London Mayor Sadiq Khan of making a politically motivated decision. Mayor Khan has criticized the firm in the past and was not pleased with the Silicon Valley app’s response. Khan said in an interview, “You can’t have it both ways: on the one hand acting in an aggressive manner for all sorts of things, but on the other hand brief to journalists that they want to do a deal with TfL.” Khan reiterated that companies which played by the rules were welcome in London.

Uber now has 21 days, until Oct. 14, to formally appeal the decision. The case will most likely be filed in London at the Westminster Magistrates’ Court. The company will be allowed to continue operating throughout the appeals process.

London is one of the world’s wealthiest capitals and one of Uber’s major markets. In the city, the company employs roughly 40,000 drivers, representing one-third of the city’s total number of private hire vehicles. Uber has launched a petition on the matter that has attracted over 750,000 signatures so far.

In the years since it began operations, Uber has faced regulatory and legal setbacks around the world. The company has been forced out of several countries, including Denmark and Hungary. Earlier this year, Uber was briefly blocked from operating in Italy and endured a two-month suspension in Taiwan.