Pinpoint test message PERMANENT_FAILURE Access Denied

I feel like I'm stuck in a parallel universe and chicken and the egg situation. I'm trying to use Pinpoint to send a voice message, but first I need to get an originating phone number. But my account first needs to be unlocked so that I can select Australia. I raised a support case, but they are telling me I need to send a test message. But how can I send a test message when I don't have an originating phone number? It's like a chicken and the egg with AWS support. Ripping my hair out!

I am trying to send an SMS Test message from Amazon Pinpoint to a verified phone number. I'm still in Sandbox mode. I tried from two different accounts. I made sure I had no SCPs interfering.

I went to Amazon Pinpoint, created a new project and then went to the Test message screen. I selected my phone number, selected TRANSACTIONAL and typed in a sample message. I pressed send and I get the following:

Message not sent: We weren't able to send your SMS message to +614xxxxxx22. Details Request Id 884 : [+614xxxxxx22: PERMANENT_FAILURE Access denied]

I am logged in using Identity Center SSO with AdministratorAccess.

I tried two different phone numbers.

What is going on? Do my accounts have some kind of freeze on them? The error message is not very helpful as is does not tell me why access is denied even though I'm using Admin access.

Thanks - difficult one...