Thanks for the info that help me a lot, whmcs.com do not say anything about special characters in their documentation.
Now my question is, do you have any problem using the USE EXIST CARD option?
when I select that option I see the last 4 digits of my credit card and ask me for my cvv number so I enter the cvv number and I click continue but I get an error.
>>>>>The credit card details you entered were declined. Please try a different card or contact support.
I am sure the cvv number is correct, then I have to re-enter all credit card info manually and the system accept the card info. is just when I select the USE EXIST CARD option.
I contact WHMCS they told me that I need to contact paypal to activate the reference transactions so I did that but I continue with the same problem, paypal told me that the problem is that whmcs is not sending the correct information when I select USE EXIST CARD option. so paypal told me to ask whmcs developers to call them to find out the problem, I did that but looks like whmcs developer dont want to call paypal.
Any one have this problem?