Didn't it take Wikileaks to reveal the email server? What do you consider 'verified'?

No? It did not? Why would you think that?

Because it would have been buried otherwise.

How is the email server an instance of corruption?

What is it an instance of? You maintain your own server for no good reason, except more control over the paper-trail; something explicitly disallowed.

The e-mail server contains many many instances of corruptions. You should check it out if you want to know more about it.