URGENT: emails being rejected

[Alex Shaw]

Hi

Our on-rev site is on jasmine.on-rev.com (50.28.38.70).

Recently, I have had quite a few emails bounce back and rejected by 
recipients, that prior to the on-rev server upgrades accepted emails ok.

Today I noticed on one of the rejected emails..

SMTP error from remote mail server after RCPT TO: xxxx
     550-delivery from 50.28.38.70 is rejected. Check at
     550-http://www.commtouch.com/Site/Resources/Check_IP_Reputation.asp. Reference
     550 code:tid=0001.0A090302.56F0A528.00EE

"whois 50.28.38.70" returned details related to the new Liquid Web servers.

I plugged the same IP address into the above mentioned site.. 
http://www.commtouch.com/Site/Resources/Check_IP_Reputation.asp

.. and it returned the following information:

IP Query Result:
IP Address:     50.28.38.70
Risk Level:     High Risk
Description:     This IP address is used for sending Spam on a regular basis

Is anyone else experiencing this?

Can this issue be resolved?

regards
alex