OSS .NET SDK has two types of exceptions: ClientException and OSSException. Both share the properties of RuntimeException.


The ClientException exception occurs when the client attempts to send requests and when the data is transmitted to OSS. For example, when a request is sent, ClientException may occur due to unavailable network connections. ClientException may occur during file uploads due to I/O exceptions.


OSSException indicates a server exception. The exception occurs because a server error message is parsed. OSSException includes the error code and information returned from OSS. It is used to locate and handle problems.

The following table describes common OSSException information.

Parameter Description
Code Specifies the error code returned by OSS.
Message Specifies the detailed error information returned by OSS.
RequestId Specifies the UUID. It is unique and used to identify a request. If a problem persists, send the RequestId to OSS developers for help.
HostId Identifies an OSS cluster. Ensure that the value of HostId is consistent with the Host (endpoint to access a bucket) used in the request.

OSS error codes

Error code Description
AccessDenied Access denied
BucketAlreadyExists The bucket already exists.
BucketNotEmpty The bucket is not empty.
EntityTooLarge The entity size exceeds the maximum limit.
EntityTooSmall The entity size is below the minimum limit.
FileGroupTooLarge The total file group size exceeds the maximum limit.
FilePartNotExist No such part exists.
FilePartStale The part has expired.
InvalidArgument The parameter format is invalid.
InvalidAccessKeyId No such AccessKeyId exists.
InvalidBucketName The bucket name is invalid.
InvalidDigest The digest is invalid.
InvalidObjectName The object name is invalid.
InvalidPart The part is invalid.
InvalidPartOrder The part order is invalid.
InvalidTargetBucketForLogging The buckets that store log files are invalid.
InternalError Internal OSS error
MalformedXML The XML format is invalid.
MethodNotAllowed The method is not allowed.
MissingArgument Parameters are not configured.
MissingContentLength The content length is not configured.
NoSuchBucket No such bucket exists.
NoSuchKey  No such object exists.
NoSuchUpload No such uploadId exists.
NotImplemented The methods are not implemented.
PreconditionFailed Precondition error
RequestTimeTooSkewed The local time set for OSSClient is deviated from the time set for the OSS server by over 15 minutes.
RequestTimeout Request timeout
SignatureDoesNotMatch Signature mismatch
TooManyBuckets The number of buckets exceeds the limit.