| AuthorizationFailedException | Authorization failed exception is thrown when error is encountered during authorizing user's permission to run the intended operations. | 
| CommunicationException | This exception is thrown when there is a client side connectivity issue. | 
| IllegalConnectionStringFormatException | This exception is thrown when the connection string provided does not meet the requirement for connection. | 
| MessageLockLostException | This exception is thrown when a receiver attempts completeorabandonorrenew-lockordeadLetterordeferoperation
 on a peek-locked message whose lock had already expired. | 
| MessageNotFoundException | This exception is thrown when a receiver attempts to receive a message with sequence number and the message with that sequence number is not available in the queue or subscription. | 
| MessagingEntityAlreadyExistsException | This exception is thrown when a subscription client tries to create a rule with the name of an already existing rule. | 
| MessagingEntityDisabledException | This exception is thrown when a client attempts to send messages to or receive messages from a disabled entity. | 
| MessagingEntityNotFoundException | This exception is thrown when a client attempts to create a sender or receiver or client to a non existent entity. | 
| OperationCancelledException | This exception is thrown when the underlying Amqp layer encounter an abnormal link abort or disconnect of connection in an unexpected fashion. | 
| PayloadSizeExceededException | this exception is thrown when user attempts to send a event data or brokered message that has exceeded the 
 allowed payload size as defined by the service. | 
| QuotaExceededException | This exception is thrown to signal that a service bus entity or namespace exceeded its quota. | 
| ReceiverDisconnectedException | This exception is thrown when a EventHubReceiver is being disconnected because of one of the
 following reason:
 
  user attempts to connect a non-epoch receiver to a event hub partition, when there is an epoch receiver connected to the partition. | 
| ServerBusyException | Server busy exception is thrown when the current entity's activity has put excessive load onto the service. | 
| ServiceBusException | This is the base exception that service bus will generate for all error cases. | 
| SessionCannotBeLockedException | This exception is thrown when a client attempts to accept a session that is already locked by another client. | 
| SessionLockLostException | This exception is thrown when a session receiver performs an operation on a session after its lock is expired. | 
| TimeoutException | This exception is thrown when the operation has exceeded the predetermined time limit. |