Please set your phone to record at 1080p HD resolution by following these instructions:
iPhone: Please set your iPhone to said resolution via Settings >Camera>Record Video. Pick 1080p HD at 30fps.
Android Samsung, Huawei, HTC, etc: This differs per phone, but these settings can mostly be found via the settings menu inside the camera app or via the general settings menu. In this menu locate the video size menu. Best setting for filming is 1080p HD and 25fps.
If this option is not available on your phone, please make sure it is not a number below 1080p and/or 25fps or above 50fps.