GMS 2.3+ Help with Screen Stretching

Hello everyone! I've been trying to export my app to my phone, but I've been having some trouble with screen stretching. My draw GUI layer is stretched perfectly, but objects' sprites are stretched vertically and their y-coordinates are off. Here is my resizing code run in a script at the beginning of the game:

var newwidth = display_get_width();
var newheight = display_get_height();
surface_resize(application_surface, newwidth, newheight);

Thanks for the help!