With a pellet stuck in the barrel all you will get is that hiss, as the air slowly sneaks around breech seal & such. Had a DAQ .458 do the same.
You may ( likely) have a mechanical problem but you must remove that pellet before diagnosing it.
A blocked transfer port would reduce psi enough to prevent the pellet exiting . A valve stme driven into/through the poppet head would cause what you describe IF no pellet stuck. Naturally could be ... ... ... .
Get that pellet out the check, if you do have a problem ( it is possible one pellet could be SO oversize that a low power rig could chamber but not make it out) , deside what you'd like to do - return or DIY repair with free parts- and give crosman's excellent service department a call.
And please let us know the issue/outcome.
John