We tried to use Twilio for 2FA and it was unreliable.

I can’t find the page now, but I’m pretty sure at one point they had a page saying you shouldn’t use it to receive 2FA codes. It’s very common for 2FA systems to blacklist numbers that are known to be used by providers like Twilio.

As far as I am aware, the only reliable way to receive 2FA over SMS is to have a real phone plan.

(Obviously SMS is a poor choice for 2FA in the first place, but sometimes there’s no other option.)

Some organizations won't let it be used, as it shows up in the databases as a voip number (even if it was a ported cell phone number). It's hit or miss

I have issues with Uber 2FA not sending a SMS to my Twillio number. Nothing arrives. 2FA via call works, just not SMS.