After completing the form and then redirected to the Paypal form I get the message below when I click the link to allow me to start a new paypal account. If I sign is using an existing/valid paypal account, I get the same error. Basically, I cannot process the payment.

Please help.

Message:

The link you have used to enter the PayPal system is invalid. Please review the link and try again.

Solved! It turns out we did not confirmed our paypal email account. Thanks

I'm getting that exact same message in the Paypal Sandbox while trying to test the payment system. As soon as I try to log in or pay with a credit card using one of my sandbox test accounts I get the message:

The link you have used to enter the PayPal system is invalid. Please review the link and try again.

I don't see how it could be an unconfirmed email address in this case as it's a sandbox account...

Any ideas?

Whoops, showing my ignorance there! It turns out (for the benefit of anyone who has a similar problem) that when using the sandbox setting for the Paypal plugin you have to have your sandbox seller account email in the email box of the plugin settings, not your actual paypal email. That's the problem.

Might be worth mentioning that in the documentation really, as it recommends you use the sandbox but no mention of needing to use a different email.

Anyway, it's solved now!

Having a similar issue on Rsmembership V1.21.14 / j3.4.8

I installed the RSMembership paypal plugin - activated it - set it to live and I get this error when redirected to paypal.
{Return To Merchant
"The link you have used to enter the PayPal system is invalid. Please review the link and try again. "
}
I'm using the same paypal email address as the paypal plugin for RSforms and it works fine.

Also, not sure if this matters but in the payment integrations screen it only gives me the ability to edit the plugin it doesnt show the publish icon.