Bar code Scanner doesn’t scan bar code's well

My Point of sale barcode scanner doesn’t work well and it’s embarrassing when I’m with a Customer to have to keep twisting and turning and fidgeting with the barcode label for several minutes before the reader will read it, allowing me to add it to the cart. is there a trick that I don’t know about? Today, I’m using it with my new iPhone 14 Pro Max but I’ve been having problems with the scanner for years whether I use it with my iPad or my iPhone, I’ve always had trouble scanning the barcodes. Even when I clean off the camera lens, it doesn’t seem to make any difference.