No, but the usual reason is that you paid to the wrong email address.
Sometimes a new seller will misspell his email when setting up his PP account.
Sometimes PP will glitch and give a buyer an obsolete email address to pay to.
Check your PP account and see if the payment has been claimed. If it has, give the transaction number to the seller. If it goes to Dispute, supply that number to the Dispute system.
If it has not been claimed, you can retract the payment and start again.