Web hosting companies have really clamped down on how emails are sent as there is so much spamming/spoofing nowadays. Years ago, it was fine but not now.
You should be able to login to your domain control panel, go to the DNS settings and add a SPF record yourself - they might do it for you but generally this is something that you should have access to yourself.
For your contact form you still get the user to fill in their email address, you just don't use that email address in the "From" field. It doesn't have to be a real email address, just as long as it uses the same domain name as the website, so for example info@salaroche.com. You will still be able to see what the user's email address is as you would include it in the message text. However when you reply to the message, you would need to copy & paste that email address into the To box manually.
For example, if I sent you a message via your contact form and add my email address e.g. me@magsdomain.com and you're using that dynamic value as the Email From address, your server is not allowed to send emails from magsdomain.com as it doesn't host that domain. It will therefore assume it's been spoofed and won't send. But if you use a static value of info@salaroche.com as the "From" email address and include the following in the content of the email:
<html>
<head>
</head>
<body>
<p>The following message has been sent via the Salaroche Contact page:</p>
<p>Name: <?php echo((isset($_POST["Full_Name"]))?$_POST["Full_Name"]:"") ?></p>
<p>Email: <?php echo((isset($_POST["Email_Address"]))?$_POST["Email_Address"]:"") ?></p>
<p>Message: <?php echo((isset($_POST["Comments"]))?$_POST["Comments"]:"") ?></p>
</body>
</html>
You can then see the email address of the person who sent the message.
