karaptsias

I found the answer in another forum, it works for me:

“To allow files bigger than 1Mb(?), I had to edit

wp-content/plugins/contact-form-7/modules/file.php
and changes 1048576 to 10048576

$allowed_size = 10048576;
This will allow ContactForm7 to accept files until 10Mb files, if we have the server configured to it.”