Usually, the problem is the dog’s rear swings too far out as his head is curling around your left leg anticipating a treat.
Giving the dog the benefit of the doubt, I’d go back to foundations and make sure Echo knows correct static heel position ie. sitting in correct position and with correct headset. Is Echo the dog in your avatar? If so, I would guess that Echo should be targeting your shoulder with your hips as a secondary target.
If you’re not sure if Echo’s rear is in correct position while sitting, have someone look for you or put a mirror (I have a cheap acrylic one) on the floor so you can see yourself.
Practice static heel position until you can maintain it for 30 seconds for 5 sets per session and about 5-10 times per day. If you have to, lure with a treat to keep head positioned where you want it.
Once you have static heel position established, you can move into dynamic heeling one step at a time. If you have taught any pivoting exercises on a upside down bucket, that will be a plus. But if not, you can use broad jumps positioned in an upright position to give Echo a guide to keep the rear straight.