Issue configuring Mail

Hello, I’m using a different host than the domain name and I used cloudflare to point to the domain name from my host and everythings work well but I got one and I think one big problem when I try to send and receive emails it’s work well but for a specific emails I got " Mail delivery failed: returning message to sender ".
this is the mail returned:

Reporting-MTA: dns; genious56

Action: failed
Final-Recipient: rfc822;[email protected]
Status: 5.0.0
Remote-MTA: dns; mail.horizonpress.ma
Diagnostic-Code: smtp; 550 Access denied - Invalid HELO name (See RFC2821 4.1.1.1)

That is an email error and as Cloudflare does not handle email at all, it wouldnt be Cloudflare related. You need to check your configuration and whether you might have to fix something in your SMTP server, but that something you best clarify on StackExchange.

Thank you