Paypal checkout error for that [UNPROCESSABLE_ENTITY]

It’s possible that the error occurs because PayPal doesn’t support the Dirham (see supported currencies: https://developer.paypal.com/docs/reports/reference/paypal-supported-currencies/). A simple test could be the following:
1. Put the site in maintenance mode
2. Change the shop’s currency to a supported one (e.g. USD).
3. Try to initiate a payment.

If the payment works in this scenario, it could confirm that the cause the unsupported currency. In that case, you will have to use a different payment processor for AED.

Hi @hasanblue,

As Diego already mentioned, AED is not a supported currency at PayPal. This information is visible in your WooCommerce system report (WooCommerce > Status) at the very bottom in the WooCommerce PayPal Payments section.
The currency list is the same but this is the link for the relevant REST API docs: https://developer.paypal.com/api/rest/reference/currency-codes/

The next PayPal Payments plugin update 1.7.0 will also improve the frontend error messages to make it more clear when, for example, the currency is not supported at PayPal. With a following update, the messaging in the backend will be extended as well.
The checkout with a supported currency should work though.
If anything remains unclear, don’t hesitate to let us know. Thanks!

Kind regards,
Niklas

Since we haven’t heard back from you, I’m going to mark it as resolved.
In case you’re still having problems, feel free to let us know!