। ॥ ३२३ ॥
In plain words
It covers over what you actually are, and bliss runs thick in it. For both reasons the causal body is called the ānandamaya-kośa — the sheath made of bliss.
Close to the Sanskrit
Because of being a coverer of one's own true nature, and also because of the abundance of bliss, the causal body is called 'the sheath made of bliss'.