Hi Josh,
first of all I want to thank you for your patience and your help!
After digging really very deep in the documentations and the code I'm quite confident, that I can provide a solution, now.
Basically you have to change a tiny bit of code to fix it.
Please open the file components\com_visforms\models\visforms.php
find the function sendReceiptMail($visform)
which starts approximatly at line 628
Almost at the end of this function (about line 729 ff) you find the following code
Code:
$mail->setBody( $mailBody );
$mail->IsHTML (true);
Replace it with
Code:
$mail->IsHTML (true);
$mail->Encoding = 'base64';
$mail->setBody( $mailBody );
Some lines later you'll find the function sendResultMail($visform)
In this function you will find the same code as above. Please replace it there too.
Could you please test, if this solves the problem?
If it does, I would release a bugfix Version of Visforms very soon.
If you prefer to I can send you the changed file for Visforms 3.4.2 via mail.
Regards,
Aicha