What to ask after failed IVF transfer with good quality embryo?

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Received confirmation yesterday that my first transfer, a 6AA PGS normal embryo, was a BFN. 😔 What should I ask my doctor when speaking with her? Egg retrieval resulted in 5 PGS tested embryos - 3 highly graded normals, 1 lower graded normal and a mosaic, so I do not think egg quality was the issue. I am leaning towards uterine receptivity or just plain bad luck as the issue for my first transfer. If anyone has had this happen before, would love to hear what to ask about and what steps were taken.

A few facts: I am 36, hubs is 38. Never been pregnant. Hysteroscopy in April 2019 to remove a uterine septum and “the most amount of polyps my doctor has ever seen”. HSG suggested one possibly blocked tube. Saline sonogram was done prior to transfer and doctor said everything looked fine.