IOS – Main Thread Checker: UI API called on a background thread: -[UIApplication delegate] PID: 902, TID: 13120, Thread name: (none), Queue name: NSOperationQueue 0x604000037a20 (QOS: UNSPECIFIED), QoS: 0 Backtrace:

Solution : use DispatchQueue.main.async { // Correct }     Updating UI from a Completion Handler Long-running tasks such as networking are often executed in the background, and provide a completion handler to signal completion. Attempting to read or update the UI from a completion handler may cause problems. let task = URLSession.shared.dataTask(with: url) { […]