How to remove my domain from Blacklist

Dear Experts,

Suddenly i couldn't send e-mails to some of my customers and suppliers and i get undeliverable with different reasons some blacklist some as below:

There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <dc.Eltek.local #5.5.0 smtp;554 Service unavailable; [] DNSBL blocked, reason:1280655905>


            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <dc.Eltek.local #5.5.0 smtp;550-5.7.1 [ 1] Our system has detected an unusual rate of>

I checked on mxtoolbox and i see that my domain is blacliksted however we are a small company with 10 e-mails and we do not send any spam!!!

How could fix that problem? maybe it is something i should do in my organixation? I have DC/Exchange server and Sharepoint server.

Appreciate the help
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Will SzymkowskiSenior Solution ArchitectCommented:
based on the mxtoolbox search - what list are you on?
There should be some links to contact the list and there site
usually explains why you are on and how to get off.
Go to their removal page and following the instructions
Jamie GillespieSenior IT ConsultantCommented:

When putting in your IP you may need to give some information. If you have been blocked because SPAM has been coming from your address just state that your equipment has been cleaned and the issues have been resolved.

Try and make sure your systems are not sending out SPAM to prevent future problems.

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