Error sending file attachment to gmail address

I am trying to send an e-mail to an address with a gmail extension. I am sending a 500kb image file as an attachment to this e-mail and I am getting the following error.

The IP address sending this message
    does not 550-5.7.25 have a PTR record setup, or the corresponding forward
    DNS entry does 550-5.7.25 not match the sending IP. As a policy, Gmail does
    not accept 550-5.7.25 messages from IPs with missing PTR records. For more
    information, go 550-5.7.25 to 550-5.7.25
    https://support.google.com/a?p=sender-guidelines-ip  550-5.7.25 To learn
    more about Gmail requirements for bulk senders, visit 550 5.7.25
    https://support.google.com/a?p=sender-guidelines.
    ffacd0b85a97d-37ee0ba7d2fsi2898770f8f.767 - gsmtp (in reply to end of DATA
    command)

There is no problem with my email settings, my ssl settings are correct. I first send a text email to the same gmail address and I do not add any attachments to this email and the email goes through without any problems.

The other gmail email address responds to my text message and when I send an email with any attachments to this return email, it does not give any errors.

Why do you think I am experiencing this strange event? Does anyone have any ideas?