We have been using Contact form 7 for several sites. Now we are using it for a new customer. The customer is receiving hundreds of repeating e-mails from the contact form we created. The strange thing is, when we use our own e-mail address, everything works fine. It's just when we choose their e-mailaddress (doesn't mather which one) they get burried under hundreds of the same e-mails (with the same message from the contact form). Same contact form, just another e-mailaddress.
Normally they don't have any problem with their e-mail. What could be the cause? We really have difficulties pinpointing the problem here (it's in the combination of their e-mail and contact form 7), and it's not convenient for the customer of course. Can it be something in the header? More important, what's the solution?