Receiving CARRIER_BLOCKED errors on Pinpoint SMS Service

Did you have your originating phone number registered? I realized that SMS messages originating from unregistered phone numbers are being dropped by carriers recently.

The registration process is taking a long time. I wonder why making it so hard for legitimate senders of SMS. All our SMS messages are in response to user's requests, e.g. OTP, so never unsolicited. Our volume is low, and there is never any complaint. I feel that the new system is making life hard for legitimate users, but fails to contain real spammers.