Problem send email Prestashop 1.7

[ricardo_es]

Please your help, I have configured the sending of SMTP emails and when I do a test of it everything is correct, however I do not receive the emails, entering with the administrator's email I see that it returns an error of:

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

  [email protected]
    host smtp.mailchannels.net [34.213.25.210]
    SMTP error from remote mail server after end of data:
    550 5.7.1 [BFD] Sender prohibited by SPF

 

I've been researching the bug and came across this link: https://bobcares.com/blog/prestashop-email-not-working/
What it tells me is the Security restrictions in the server

The problem is that I cannot find the files according to the solution proposed by editing the /tools/swift/Swift/Message.php file (I think that this is because I am using Prestashop version 1.7.6.5).
As you could correct this error, any help is appreciated.

My Settings:

Prestashop:1.7.6.5

Php:7.2.31

Edited August 25, 2020 by ricardo_es (see edit history)