I bought a FOB of amazon and it would not work the dealer could not program it.
I ending buying one from the dealer expensive but it works.
Now I did buy some keys from amazon and the dealer cut them for like 30$ and programed them and they worked just fine.
So yes i think you could have a bad FOB they seem to be picky on jeeps.
The vendor was Discount Keyless for both items they refunded me for the FOB just took a awhile, but like I said the keys work fine got 3 now.
2000 Jeep grand Cherokee
I6, selectrac, dana 30 front 44a rear
Stock not lifted.