messages to hotmail being rejected

when I send an email to a hotmail account from eM I get a message from MAILER-DAEMON@mailout-us.mail.com saying:

Hi. This is the qmail-send program at mailout-us.mail.com.
I’m afraid I wasn’t able to deliver your message to the following addresses.
This is a permanent error; I’ve given up. Sorry it didn’t work out.

:
Connected_to_65.55.37.120_but_sender_was_rejected./Remote_host_said:_550_SC-001_(COL0-MC4-F16)_Unfortunately,_messages_from_74.208.122.35_weren’t_sent._Please_contact_your_Internet_service_provider_since_part_of_their_network_is_on_our_block_list._You_can_also_refer_your_provider_to_http://mail.live.com/mail/troubleshoo…

I can send the same message to the same hotmail account from the web (mail.com) without a problem and can also receive mail from hotmail into the eM client

It looks like some server of your email provider (mail.com) is black-listed, possibly because the service was abused by spammers. Please contact your email service provider and send them the error above. They should be able to help you and get their server off the black list.

Note that the Web Mail at mail.com may use different server of the same provider which isn’t blacklisted.