Sorry I am a bit lost here. How is this a paradox? Now we can conclude that if this sentence is true, then Santa Claus exists, then necessarily, if Santa Clau

Sorry I am a bit lost here. How is this a paradox? Now we can conclude that if this sentence is true, then Santa Claus exists, then necessarily, if Santa Claus does not exist, this sentence is false, but if this sentence is false, we cannot conclusively make any statement about the existence of Santa Claus. Even if you modified the above statement to iff this sentence is true, then Santa Claus exists, the above would still apply. If the sentence is false, then the iff condition is also false, so if the sentence is false, Santa Claus may or may not exist.