Storage Studio says my S3 region looks invalid. What's wrong?
Short answer: You probably entered an Availability Zone ID such as aps1-az1 instead of a region like ap-south-1. Storage Studio blocks the save and suggests the right region; for a saved account, use the banner's one-click fix or Edit the region.
You've most likely entered an Availability Zone ID (like aps1-az1 or use1-az2) in the Region field. That's a different identifier, so the connection fails. Regions look like us-east-1, eu-west-3 or ap-south-1.
When you're adding the account, Storage Studio stops the save and tells you the parent region. For an account you already saved, its details show a banner with a one-click button to use the correct region and retest. You can also click Edit and type the region yourself — it's the region you chose when creating the bucket.