Boost Mobile is Sprint (CDMA). If you have the AT&T model (the one with the intel instead of qualcomm modem) then it doesn't support CDMA (Sprint or Verizon).
I called Verizon 2 months ago, they checked the imei number to see if it would work on their network. They said it will. Does that mean it will work on boost mobile since Verizon is CDMA?
I updated my post above with the specific model numbers. Which model number is your iphone X?
Awesome, your Apple iPhone 8 Non VZ CDMALess is a perfect match for our network.
This topic has been discussed on macrumors.
https://forums.macrumors.com/threads/switched-from-at-t-to-verizon-but-i-have-a1901-model.2096933/
A1901 iPhone with intel modem will work with LTE service but cannot use fallback 3G CDMA signal if you lose LTE signal.
So if Boost Mobile has hampered coverage (i.e. Sprint LTE signal coverage not the best), then likely no signal might occur on your A1901.