Exactly the same boat, just had our second transfer fail with what seemed like good quality embryos. My clinic (NHS) have assured me that all my tests and investigations are clear and sometimes embryos just don’t implant and it’s down to mother nature who can be cruel. So not really answers as such but I have the peace of mind that it’s sometimes just down to luck. Starting to try and mentally prepare for round 2 as no embryos left from round 1 now. X