Hi
Jack •,
Welcome to Micrsoft Q&A forum and thanks for using Azure Services.
As I understand, Azure Cache for Redis upgrade is taking longer than expected and used to work fine earlier.
From the description given in the question, it looks like that a management operation, like scaling or patching, is in progress on your cache. All other management operations are blocked until the ongoing operation is completed. Usually, the ongoing management operation should be completed in a few hours. If you see this error even after 12 hours, please let us know.
Please check back after 12 hours or a days and let is know if the issue still exists.
Thank you.