"WHM >> Exim Configuration Manager >> Basic Editor" on the cPanel server you are sending the message to and add the IP address the message is coming from under the "Trusted SMTP IP addresses" option.


cuenta@remotedomain
    (ultimately generated from cuenta@localdomain)
    host remotedomain [xxx.xxx.xx.xx]
    SMTP error from remote mail server after RCPT TO:<cuenta@remotedomain>:
    550-Verification failed for <cuentahost@localhostname>
    550-The mail server could not deliver mail to cuentahost@localhostnam.  The account or domain may not exist, they may be blacklisted, or missing the proper dns entries.
    550 Sender verify failed