Hi Luke,
Please confirm that you created the VM with Standard security. You can do this by navigating to the VM in the Azure portal -- Overview blade. See screen snippet below:
If the VM wasn't created with Standard security you will need to create it again and make sure to select Standard, similar to below screenshot:
Please click Accept Answer and upvote if the above was helpful. Add a comment below if something is unclear or you still need assistance.
Thanks.
-TP