When entering incorrect data, an error is displayed but focus is redirected to the field in error without any indication of why focus is redirected. Low vision users who may have the screen zoomed or Talkback users may miss the error message if their attention is not drawn to the message.
Display the error message adjacent to the input field that triggered it and/or move focus to the error message (when magnification is enabled, items in focus should pan into view)
The error message should appear onscreen until it is explicitly dismissed.
Consider using a native dialog/alert/notification box.