You can no longer generate referral links for two of the most popular Chase cards, the Chase Sapphire Reserve and Chase Freedom. Both pages where you could get you referrals, no show a message saying “Thank you for visiting Chase… Refer-A-Friend promotion has concluded”. You can see the referral page for Sapphire Reserve here and Freedom here.
This is probably temporary. I expect referrals to be an option again soon. For now it’s not exactly clear if existing referral links will still earn the referral bonus. Looks like they should since links still work.