Reports of difficulties with the Monzo app began around 11 a.m., escalating to over 3,000 users reporting issues by 1 p.m. and more than 1,000 continuing to report problems by 4 p.m. Users in major cities, including Liverpool, Leeds, London, Birmingham, and Edinburgh, experienced disruptions. A survey revealed that 76% of users faced issues, with 11% struggling with funds transfers and 9% with mobile banking. Monzo acknowledged the difficulties, stating that the app was "experiencing issues" and full functionality was temporarily unavailable, but essential services like card payments and cash withdrawals remained operational. Monzo's spokesperson indicated they were addressing a technical issue and had switched to their backup system, Monzo Stand-in, allowing most features to continue. Downdetector is a platform for users to report issues with various services, tracking problems by comparing user reports to typical levels for that time.