Ask HN: WTF why can’t me and friend SMS

So my friend and I cannot sms each other - he doesn’t receive and I don’t receive sms… T-Mobile vs Verizon (but here is the crazy part I’ve had multiple carriers over the years - and lit today we still can’t sms… And I’ve worked in the cell industry - but wtf? Why can’t our phones text — AND IT BEEN FROM MULTIPLE PHONE NUMBERS (No, neither of us has blocked one-another!) Anyone have some hints?