E-mail not receiving attachment.

Hi!
First of all, let me congratulate for this awesome plugin. I know almost nothing about programming, but is really easy to recognize the awesome work you’ve put in this.
So, I’ve created a form that includes the file upload feature. The tags are correct in the Attachments field. The uploads folder is created, with the parent folder set with the 777 access. But I’m not receiving any attachment… or something like it.
What happens is that, in the end of the e-mail, after the last info set in the Mail Body field, in the form settings, I’m receiving this message (the info between <> are my comments):

“[…]
—
Este e-mail foi enviado de um formulário de contato em Leste Corretora (http://lestecorretora.com.br) […] <this is the standard pt-BR message related to where does the form comes from>

–b1_896f8cd5f6365b55ae0eea724d485ec3
Content-Type: image/png; name=”CNH.png”
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename=CNH.png

iVBORw0KGgoAAAANSUhEUgAAA9AAAAGWCAYAAACQMGuwAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAGwTSURBVHhe7b3tkxzVneer/SMI3jhiIpgXS+wb
AnlszFx7FOvFcB2NgzsK37Ec9hjCjAazMuGHO9fIy6CJxe61BxEDgW[…]<… … …>”

And this is how it goes with every attachment I try. (My form requires 4 docs to be sent. The files I’m trying to attach have only 27 kb each.)

Pretty sure I should clarify, it’s a long form, and I’m using a plugin called Contact Form 7 Multi-Step Forms, that unfornately we really gotta use (it’s necessary to this form to be divided through 4 pages). But EVERYTHING works just fine. The plugin is actually able to correctly get and send every information filled in the other forms’ pages, and actually the files are attached only at the very last page, so I don’t think this is the problem.

Does anyone have any clue about what it might be? Sorry, as I stated, i’m pretty newbie with programming.

https://wordpress.org/plugins/contact-form-7/