[Travel Insurance] Improve e-visa application support

I (F23) am an American trying to get an evisa for a solo trip in Vietnam next month. It is not letting me pay, and I have no idea what to do. I have double-checked that it’s the correct website. I have made five applications with three different emails, and I have used two different internet browsers. I even tried once on my phone, and I get the same message. It doesn’t even let me input my card information. I get to the last step, and try to continue to payment and it just says there was an error and make another application. I literally have no idea what to do if the website won’t let me pay. I have a card that it says it’ll take, and when I make a new application, I can input my bank information but then it just says error. I researched this problem up a ton, and none of the advice, like making a different email or waiting a day, has helped. I have used safari, Microsoft edge, chrome, and Firefox and I get the same message. I have emailed the website twice, but I seriously doubt I’ll get anything back. Whenever I look it up, every one says it’s a simple process, but it seems impossible to get the payment through. I’ve checked my account, and I haven’t even been charged. I really need some help because I sincerely don’t understand why I can’t get this visa. If anyone has any recent experience, I’d really appreciate some advice. And to the moderators, please let this post go through because I don’t know where else to ask and I’d very much like to still go on my trip.