Can not add my pass to airport parking to my wallet

The support article you arrived here from should provide you with the steps to take if you cannot add a card to the Wallet app on your iPhone. Note that not all cards, passes, etc. can be added as their provider must approve them for use with the Wallet. This may be the case here for this airport parking pass.

Ok, sorry that didn't help. Your next step, as per the article, will be to contact Apple Support directly. To do so, simply select the "Get Support" link in the upper right-hand side of this forum's web page.