I am just experiencing my 6th failed ivf cycle with donor eggs. two re's can't figure out the problem. is there anything you recommend investigating?

You could get 1 more: Opinion. Otherwise, as the eggs are donor eggs it's possible your body won't accept the embryo. You have two competent reproductive endocrinologists and presumably a maternal fetal medicine specialist, so if the procedure doesn't work, you can keep trying, see what another doc thinks or start looking to adopt a baby. Sometimes the mind is willing but the flesh won't yield. Consider other options.