Once we start a campaign it will say sending 0%. when we refresh the page to see if it's sending, the status continues to be switched back to paused. He has an active working delivery server, which we rechecked and re-validated to make sure. And we got the validation emails via his delivery server properly.
Also, in another thread I saw you say if quota is not full to 1005, check the time period. I have the quota set to 1 million emails every 1 month. He has sent less than 8,000 emails ever.
The other setting I verified is that the customer is not active. And he's not, it shows him as active in the backend.