HTTP status code 412-Object Storage Service(OSS)-阿里云帮助中心

OSS returns HTTP status code 412 when a conditional download request fails because the object does not meet the specified preconditions.

PreconditionFailed

Error message: At least one of the pre-conditions you specified did not hold

The following two request headers can trigger this error. Identify which header you specified and apply the corresponding fix.

Header	Trigger condition	Fix
`If-Unmodified-Since`	The object was modified after the time you specified.	Set the header value to a time equal to or later than the object's last modified time.
`If-Match`	The ETag in the header does not match the object's ETag.	Set the header value to the exact ETag of the object.

Trigger: The object has been modified after the time specified in If-Unmodified-Since.

Fix: Set If-Unmodified-Since to a time equal to or later than the object's last modified time.

Trigger: The ETag value in If-Match does not match the ETag of the object.

Fix: Set If-Match to the exact ETag value of the object you want to download.