Credit card denied for château vaux-le-vicomte!

I'm assuming that you are using Visa or MC and not AMEX? If so, I would try using a different browser. If you're using Chrome, maybe switch to Firefox or Safari (if you have a Mac). Chrome seems to get these glitches now and then so using a different browser might do the trick.

By the way, the website link above is actually their email address. I think this may be what you were on when you tried to purchase it? https://billetterie.vaux-le-vicomte.com/selection/timeslotpass?productId=101799405910&gtmStepTracking=true

When this has happened to us from time to time, I have switched computers and used a different browser and sometimes that gets it done, so I second the advice above.

If it's available, a Paypal option can succeed when a US cc fails.

Can you register your Visa card with "verified by Visa"?

Some card processing companies used in France will process only French credit cards, which are cards that immediately debit the amount. For example, several major stores won't accept my cards for online shopping but will in the store: IKEA, Monoprix. I can use only a card issued by a French bank. It would be strange for a tourist attraction, but it's possible.
You could try a debit card.

Thanks for your responses, everyone. You're right, Mardee, the website I posted is their email. I've sent them 3 messages so far. I am, indeed using Visa, 2 different cards. And, yes I was using chrome. I tried with 2 different Visa cards with no luck. I switched to Firefox. No luck. I changed computers. Tried with Google Chrome and with Firefox on different computer. No luck. I switched to an Apple Computer and tried Safari. Same result. I've tried all of these using English and also using French.
I've tried accessing chateau-vaux-le-vicomte various ways with various cards, various browsers and various computers. No luck.
I noticed today during 1 of my many tries there was a notice that said chateau-vaux-le-vicomte was closed until April 4. I'm wondering if they won't actually be selling tickets until then. Makes no sense to me but who knows? I'm hesitant to wait until April 4 as there is only one possible date I can be there, which is the 1st day they are open for the candlelight tours. I've contacted "verified by visa". They swear there is nothing on their end that would prevent this transaction. Also checked with Chase and they confirmed it's not being blocked on their end. I hate PayPal from past experiences and don't even know if I can still use them. I have an ATM card for my bank which I guess is the same as a debit card. I've never used it as a debit card for purchase, only to withdraw euros as necessary from an ATM machine. I have no idea if there's a foreign transaction fee for doing this or if it's even possible to use this card for purchase. I'm trying not to whine but I am feeling pretty defeated.

I see tickets available through the FNAC Spectacles website. I switched it to English, see the candlelight option, can choose the option for non-FNAC members. The only hangup is it says to 14:30, so it still needs clarification. But look on the FNAC website.
As I said above, it could be an issue caused by the card processor.

I constantly run into problems with US credit cards when purchasing anything online in France. It is the French processors who deny most of these purchases, Visa/MC in the US never sees a request.

For example, there has been an issue for many years purchasing tickets from the SNCF using a US credit card. Most of the SNCF difficulties have been resolved, but the issue remains elsewhere. Workarounds are almost impossible.

Success! I did exactly the same thing I did the 1st 3 or 4 times I tried with the same computer, same browser, same credit card etc. and this time they liked it! I have no idea why this is suddenly working but I'm grateful. Thanks, Bets for the tip about FNAC as well as your earlier post. Don't expect to use my card for online shopping while in France but this is good to know just in case of Covid. Tocard, I, too have run into the issue when purchasing tickets for the SNCF. I couldn't remember how it resolved the last time I did it which was maybe in 2018. BTW, for future reference for those of us who cannot seem to break through a French website's barrier someone just suggested to me that I purchase them using my cell phone after turning off Wi-Fi. That way it goes through a whole different system which may or may not work.