The Teradata system places locks on objects during the time that transactions take place. For example, if a transaction is taking place on a table, you cannot run a read operation until the previous transaction is complete.
If there are locks on objects included in a job, DSA waits indefinitely until the locks are released. When this happens, the object status in the Log tab of the Job Status view displays "BLOCKED" to indicate that the object is locked. Release the locks so that the job can be run when all of the objects can be accessed.