Why would your best friend or someoneyou mutually considered a good friend suddenly ghost you?

Is there a way to figure out if they blocked youon Signal if you can still technically message them?

Edit: he seems to have blocked me or hasn't used Signal since a single emphatically non-controversial/non-hurtful comment so he either blocked me or hasn't opened Signal for >month. He's not responding to anything else either so he's either depressed or blocked+done with me.

Edit: I'll know when it comes birthday time. I'm not a Bridezilla about birthdays but it would be unusual for him to not wish me one. He's never not done so. I'll have my answer when that happens 🙏 (namaste) If he wants to be a dick about it and leave me in the dark totally those days are fortunatley numbered :/

Edit: we're white and very (North)-American.