can't send nor receive emails from webmail nor thundirbird. No reverse DNS (PTR)

Hello,

I can't send nor receive emails from domain.com/webmail.

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Thunderbird says this when I try to send an email:

Sending of the message failed.
The certificate is not trusted because it is self-signed.
The configuration related to smtp.peruvian-maca.com must be corrected.


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intodns.com shows this error:

Reverse MX A records (PTR)
ERROR: No reverse DNS (PTR) entries. The problem MX records are:
90.4.80.44.in-addr.arpa -> no reverse (PTR) detected
You should contact your ISP and ask him to add a PTR record for your ips

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Any suggestions?

C.N.