[Slackbuilds-users] Email rejection

[Slacker build user]

I have seen others post here when their submissions were rejected due to email 
rejection - my turn.

When attempting to upload a script I get:

slacker at slaphappygeeks.com was rejected by slaphappygeeks.com.
Go back and enter a valid E-Mail address.

Of course, I have no idea why.

I have looked over my email manager (common web host, CPanel) and see nothing 
for setting graylist.

Can someone point me in the right direction please...

Thanks