Hi Andrew Kerekes,
Thanks for reaching out to us on Microsoft Q&A forum.
From your question we understand that you are facing an error while validating your storage account name.
Could you please check whether "Microsoft.storage" is registered or unregistered under resource providers?
If it is not registered under resource providers, there might be a chance of getting this error.
For more details please refer: Register resource provider.
And, for reference please find the attached screenshot:
If the issue still persists, please do let us know. Glad to help.
I hope this information is helpful, please Upvote & Accept Answer so that it would be helpful to community members.
Thank you.