Zoho doesn't retrieve all my emails from my server host

Zoho doesn't retrieve all my emails from my server host

I'm using GoDaddy as my hosting server, and I've configured my MX records to get all the emails in Zoho Mail.

I'm receiving emails in Zoho Mail correctly but there are some emails in my webmail (godaddy) not retrieved by Zoho Mail.
Those emails are created from the webmail site or from my website contact form using PHP mail() function.

I've tried to use PHP Mailer with SMTP config with no luck. (Connection refused from smtp.zoho.com)

Any ideas please?

Thank you in advance!