"an error occurred" when trying to pay an invoice

[stormy]

We've had reports from customers about this. They click on the invoice link on the email notification and they get this "an error occurred" error message. We haven't been able to troubleshoot it, until today it happened to me.

 

I received an invoice from a company that also uses WHMCS. I clicked on the invoice link. I was then prompted to log-in, and after logging in, that's when the error happens.

 

I've been able to duplicate it, simply by logging out, closing the browser and clicking on the email link again.