I have WP e-commerce installed on my blog and for some reason the notification e-mails to me and the Track and Trace e-mails I send to the costumer through WordPress only send sporadically. I receive mayby 1/3 of the notifications and when I send T'n'T e-mail I can usually send 5-10. Then it just tells me: "E-mail could not be sent. Plese try again later."
As far as I understand it just piggybacks on WordPress' own mailsystem.
Does anyone have any ideas?