3rd failed frozen embryo transfer. What am i missing?

Hi, I just received word that my 3rd frozen embryo transfer didn’t work.

Over the last 3 years (4 and a half total

trying) we’ve done:

- 3 IUIs one ending in cp

- 2 retrievals with 5 pgs normal embryos

- 3 embryo transfers with 1 ending in cp

- 1 era after my first failed transfer

- had 2 natural positives ending in cp

My second transfer I did a hysterscope and endometrin scratch. That round failed and endometrin was 8.7mm.

The 3rd I incorporated intralipid infusion, blood thinners, and a steroid. This time got to 8mm and then shrunk to 7mm after progesterone.

I have a call with my doctor later this week but am at a loss. What else should I ask for? Any ideas about ways to increase uterine lining besides vitamin e and l-Argine ( I take those).

What else should I try?