It could be caused by a fluctuation in capacity, but could also be due to other capacity constraints in the region. Please see this thread for a possible explanation. You can submit a SKU request to Azure Support as noted here.
Hope this helps. Let me know if you are still having issues or need assistance opening a support request.
If you still have questions, please let us know in the "comments" and we would be happy to help you. Comment is the fastest way of notifying the experts.
If the answer has been helpful, we appreciate hearing from you and would love to help others who may have the same question. Accepting answers helps increase visibility of this question for other members of the Microsoft Q&A community.
Thank you for helping to improve Microsoft Q&A!