Hello Kim,
unfortunately the internal browser of versions of WebSite X5 before 2022.2 no longer supports the onboarding of PayPal after some changes on their end that took place near the beginning of 2024.
If a project already has the payment method configured, it should still work, but it is not possible to remove it and add it again.
You will need to either purchase a more recent version of the software, or use the deprecated PayPal payment method.
I remain available.

I never removed PayPal it just stopped working. Do you think the only solution will be the upgrade? I don't want to use the deprecated PayPal.

Hello Kim,
unfortunately with versions prior to 2022.2 it is no longer possible to repeat the onboarding in case the connection has been lost, exactly.

No worries. I've updated X5 and put all info in to the PayPal set up. When I click ok I get a pop up saying - enter all the mandatory data to continue. I have entered all the data but still getting the message!

I've fixed the pop up issue, installed PayPal but it's still not working when you purchase from my store.