recurring payments for five years - wordpress

Question

I am setting up a donation page (in WordPress) for a non-profit that has a "5 YEAR DONATION PLAN". Members pay $100 per month for 72 months.
I am attempting to use PayPal's example for recurring payments:
<form action="https://www.paypal.com/cgi-bin/webscr" method="post">
<!-- Identify your business so that you can collect the payments. -->
<input type="hidden" name="business" value="alice#mystore.com">
<!-- Specify a Subscribe button. -->
<input type="hidden" name="cmd" value="_xclick-subscriptions">
<!-- Identify the subscription. -->
<input type="hidden" name="item_name" value="Alice's Monthly Digest">
<input type="hidden" name="item_number" value="DIG Weekly">
<!-- Set the terms of the recurring payments. -->
<input type="hidden" name="a3" value="69.95">
<input type="hidden" name="p3" value="1">
<input type="hidden" name="t3" value="M">
<!-- Set recurring payments to stop after 6 billing cycles. -->
<input type="hidden" name="src" value="1">
<input type="hidden" name="srt" value="6">
<!-- Display the payment button. -->
<input type="image" name="submit" border="0"
src="https://www.paypalobjects.com/en_US/i/btn/btn_subscribe_LG.gif"
alt="PayPal - The safer, easier way to pay online">
<img alt="" border="0" width="1" height="1"
src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif" >
Here is my code, edited:
<!-- Identify your business so that you can collect the payments. -->
<input type="hidden" name="business" value="kcarson#basinwidefoundation.com">
<!-- Specify a Subscribe button. -->
<input type="hidden" name="cmd" value="_xclick-subscriptions">
<!-- Identify the subscription. -->
<input type="hidden" name="item_name" value="Sky's The Limit - Galaxy72">
<input type="hidden" name="item_number" value="STL-G72">
<!-- Set the terms of the recurring payments. -->
<input type="hidden" name="a3" value="100.00">
<input type="hidden" name="p3" value="1">
<input type="hidden" name="t3" value="M">
<!-- Set recurring payments to stop after 72 billing cycles. -->
<input type="hidden" name="src" value="1">
<input type="hidden" name="srt" value="72">
<!-- Display the payment button. -->
<input type="image" name="submit" border="0"
src="https://www.paypalobjects.com/en_US/i/btn/btn_subscribe_LG.gif"
alt="PayPal - The safer, easier way to pay online">
<img alt="" border="0" width="1" height="1"
src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif" >
If I use the PayPal example, as is, the PayPal page displays exactly as it should. However, when I edit the code, with our specifics, I get this error message:
"The link you have used to enter the PayPal system is invalid. Please review the link and try again."
Thanks for your help!

Answer 1

You are passing the srt=72 which is not allowed . The allowed values for the srt is form 0 - 52 . Here is what docs say :
srt :Optional Recurring times. Number of times that subscription payments recur. Specify an integer with a minimum value of 2 and a maximum value of 52. Valid only if you specify src="1".
You can refer the documentation here.
Once you set it to any value between 0- 52 , it should work fine .