FET protocol success??

What protocol did you guys use for your FETs that worked?? I have had 5 FETs now all using genetically tested and normal (very high grade - As and Bs) embryos and they have ALL failed. Have tried different protocol each time (natural, programmed, highly programmed with high doses of progesterone etc and then two more natural cycles) and they have all failed. Have been tested by 3 drs by all this have had 6 other opinions. No one knows why they have failed. Please someone tell me am I missing something? What protocol worked for you all?? Please help me. I’m so lost.