Gmail and Hotmail marked as spam

Question

First of all, I want to thank you for your time. I\'m having a hard time getting my head around this problem.

With reference to this thread we\'ve dediced to implem

Answer 1

It is also possible that if the new IP address has been previously blacklisted by Google or Hotmail or any of the third parties they use (even before it was owned by you), the blacklist is still in effect.

In addition to mxtoolbox.com, I'd also checkout Spamhaus's lookup (http://www.spamhaus.org/lookup.lasso). Many providers use their XBL, PBL, and DBL advisories to maintain a blacklist.