FTP details attached. I'm using the WebAssist Universal E-mail extension and I have the FROM and TO set to my client's e-mail address because it just plain doesn't work at all if you set FROM to be the e-mail address that's entered by the customer in the form.
I have the customers e-mail address, which is what's causing the form script not to work when entering either a Yahoo, Hotmail or AOL address, set as the Reply To address in the Additional Headers section of the behaviour wizard.
The host has set up their own PHP mail script and it doesn't block any of these e-mail addresses which, they say, 100% points towards the form script as being the problem.
If that's the case, I'll have to change every form I've installed that uses the WebAssist Universal E-mail extension which is, pretty much, every form I've ever installed so this is quite a crisis really.
Hoping that you can track down what's happening asap.