If you have an*.appspot.com default bucket, your Firebase project must be upgraded to thepay-as-you-go Blaze pricing plan byFebruary 03, 2026 to maintain access to your default bucket.Learn more.

Sometimes when you're building an app, things don't go as planned and anerror occurs.

When in doubt, check the error returned, and see what the error message says.

Note: By default, aCloud Storage for Firebase bucket requiresFirebase Authenticationto perform any action on the bucket's data or files. You can change yourFirebase Security Rules forCloud Storage toallow unauthenticated access for specific situations.However, for most situations, we strongly recommendrestricting access and setting up robust security rules(especially for production apps). Note that if you useGoogleApp Engine and have a defaultCloud Storage bucket with a nameformat of*.appspot.com, you may need to considerhow your security rules impact access toApp Engine files.

If you've checked the error message and haveCloud Storage Security Rules that allow youraction, but are still struggling to fix the error, visit ourSupport page and let us know how we can help.

Handle Error Messages

There are a number of reasons why errors may occur, including the filenot existing, the user not having permission to access the desired file, or theuser cancelling the file upload.

To properly diagnose the issue and handle the error, here is a full list ofall the errors our client will raise, and how they can occur.

Name	Reason
FIRStorageErrorCodeUnknown	An unknown error occurred.
FIRStorageErrorCodeObjectNotFound	No object exists at the specified reference.
FIRStorageErrorCodeBucketNotFound	No bucket is configured forCloud Storage.
FIRStorageErrorCodeProjectNotFound	No project is configured forCloud Storage.
FIRStorageErrorCodeQuotaExceeded	Quota on yourCloud Storage bucket has been exceeded. If you're on the Spark pricing plan, consider upgrading to thepay-as-you-go Blaze pricing plan. If you're already on the Blaze pricing plan, reach out to Firebase Support. Important: StartingFebruary 03, 2026, theBlaze pricing plan will berequired to useCloud Storage, even default buckets.
FIRStorageErrorCodeUnauthenticated	User is unauthenticated. Authenticate and try again.
FIRStorageErrorCodeUnauthorized	User is not authorized to perform the requested action. Check your rules to ensure they are correct.
FIRStorageErrorCodeRetryLimitExceeded	The maximum time limit on an operation (upload, download, delete, etc.) has been exceeded. Try uploading again.
FIRStorageErrorCodeNonMatchingChecksum	File on the client does not match the checksum of the file received by the server. Try uploading again.
FIRStorageErrorCodeCanceled	User canceled the operation.
FIRStorageErrorCodeDownloadSizeExceeded	Size of the downloaded file exceeds the amount of memory allocated for the download. Increase memory cap and try downloading again.