I have correctly configured Paypal Express Checkout in my backend.
The solution is enabled at the Express Checkout configuration.
Display in shopping cart set to "yes"
It is enabled in the advanced tab in configurations.
However it does not show up in the cart as a payment option.
I set "Display on Product Page" to "Yes" and the button shows up, but if you click it, it takes me to a blank page with the following url:
https://merkazhasofrim.com/paypal/express/start/button/1/ (merkazhasofrim.com being the website)
Theme support claims it has nothing to do with the theme template.
What could be the matter?
Judging by the page, some error occurred on the server: https://www.gyazo.com/fdadf3dad20f7dbccb9cd2fc7a678236
In order to understand the reason why it came to that, you need to check your server logs. To find the log file, check your server settings. That's the only way to figure that out.