Some internet services use "short-codes" for their mass messaging services and verification messages. Unfortunately, our telephony provider does not support all short-code types at this stage, only some.
A few workaround options if you experience this issue:
1. If your website/app has the option to verify via email
2. If your website/app has the option to verify via phone call
3. Use your personal phone number to get verified, then change your phone number in their settings to your Sudo phone number. You just won't be able to use Sudo for verification texts at this time.