I have the paypal IPN module installed and have the primary paypal email address entered into the module configuration. I buy something on my store, get redirected to Paypal site, complete the payment process and I don't get an order number.
Here's the output from the Paypal IPN modules log file (the only thing I modified in the output was to change the email address to MYUSER AT MYDOMAIN DOT COM, and yes in the log file they are identical).
Mon Oct 2006 17:26 -- IPN WARNING::Transaction email address not matched. From IPN = MYUSER AT MYDOMAIN DOT COM: From CONFIG = MYUSER AT MYDOMAIN DOT COM
Mon Oct 2006 17:26 -- IPN FATAL ERROR::Transaction did not validate
Any idea why it says the Transaction email address doesn't match?