When I try and check out with Paypal the message says
Hank here from Shopify.
Normally that message can appear in a number of ways, which I will share with you.
It can appear if you are still on a trial plan as the checkout is disabled when not on a paid plan. If you are logged in to your admin whilst browsing your site as a customer, have edited your theme code and it is showing a broken link, or if there is something wrong with your PayPal account. Having your website password-protected can also affect external gateways.
Sometimes it can also be a case of it being a localized issue like your browser or Internet Service Provider (ISP). Can you try opening your website using incognito mode to see if you are able to purchase via PayPal? If it does, then can you try clearing your cache?
Lastly, can you share your store URL, and I can test this on my end for you?
Any further questions, let me know!
All the best,
What payment gateway are you using? Have you reached out to them already if not using Shopify payments?
Also, can you share a screenshot of the error you are seeing?
As you mentioned the incognito window resolved the PayPal issue, have you tried clearing your cache since?
What payment gateway are you using?
From your screenshot, it looks like it is a temporary issue, or something more localized. But reaching out to your payment gateway (Settings > Payments) should give you more information if there are any issues.
But no, you should not need to set up directly with Visa/Mastercard, etc.