Pinpoint not receiving SMS

We have a few departmental accounts that force 2FA via phone number with other vendors. I was hoping to use a Pinpoint phone number to receive these 2FA texts and then send them by email to authorized users via SNS.

I have it working for 2FA SMS messages coming from one vendor, but there are 2 other vendors whose text messages don't get received by Pinpoint. If I use my USA phone number to receives the 2FA SMS messages then I receive them, but when I switch the phone number to the AWS pinpoint number the SMS messages never get received. Are certain phone numbers blocked by Pinpoint? The text messages are coming from US numbers to an AWS US number. One of the failed 2FA SMS messages is coming from a "short code" number, but the other failed 2FA SMS message is coming from a regular full US phone number. Any help would be appreciated.