My advice is bring it to Apple store, they will give you a free SIM and you can then activate it online there (via boost website).. It was the last number on the iPhone box label which I entered on the website for IMEI. I then entered sim number and it worked.
Doesn’t make sense that you’re having locked phone issues since it’s unlocked. Genius Bar may be able to help.
I was phone less almost 24 hours. Apple got me back.
The SIM that Apple Store gave me for Boost for my unlocked iphone XR is SIMGLW416TQ.
That is not the one Boost said I needed either.
I also lost my $25 BYOD Unlimited plan.
I will go to the Apple store tomorrow and see if they can get it all sorted out for me. I’ve checked the IMEI number on every single cell phone network and it is compatible except for Boost.
I wonder if this has something to do with the completion of the T-Mobile Sprint Merger that was supposed to be complete by 1stQ 2019?
Also, why is it so hard to activate a phone Boost actually sells? It seems if you purchase the Xr from them, it works fine when you get it and it activates correctly? Is the unlocked Xr problem because they want you to purchase the phone from them?
The only issue I have with that is (when not on sale) you can buy an unlocked Xr for the same price at BB or Apple, so why buy a locked down phone you must use for a year with a pre-pay service? I don't think its right you are paying the same price and having your phone locked to Boost for a year, and then that's even if they will unlock it for you.
Boost should really post a sticky here on how to activate the phone step by step for everyone so there are no issues.