If you mean you don't see it on your prequalification page, that is normal, since you have the card. I don't think Amex shows you prequals on cards you already have (could be wrong, though).
It still appears for me when you go to the main site, choose Cards, choose Travel Cards, and check the list of cards.
Here's what I see
@KJinNC wrote:If you mean you don't see it on your prequalification page, that is normal, since you have the card. I don't think Amex shows you prequals on cards you already have (could be wrong, though).
It still appears for me when you go to the main site, choose Cards, choose Travel Cards, and check the list of cards.
Sometimes a card you already hold will in fact be displayed on the prequalification page but there will be a "Your Card" annotation and instead of "Apply Now" you may see "Add Another User".
I just checked the prequalification page and discovered I'm pre-approved for another personal Gold Card. 
Well, I have a weird profile, so what I experience may not be the norm. I was prequalified for Delta Gold, applied, insta-denied, reconned, got a letter a week later saying they were standing by the denial. The very day I got that letter, I noticed I was now preapproved for the same card, applied, and got it. Checked prequalification, and it was no longer there, nor was anything else. But, I was preapproved for a bunch of other cards, applied for a Hilton card, got it. So, my limited experience leads me to not take prequalification very seriously. Preapproval has been solid for me so far, though.