Recurring payments are not working - "The link you have used is invalid"

If you are redirected to PayPal and such an error is generated when using recurring payments, please make sure that the Membership Length is greater than 1 day as PayPal does not accept recurring payments if the period at which the payment must me made is less than 1 day/24 hours.

If recurring payments are not accepted when made through Authorize.net, then the payment may simply not be processed due to the same reason. As Authorize.net accepts recurring payments only if the interval of the payment is at least 7 days. In this case you will need to set the membership length to a value greater than 7 days/1 week.