No Data Received

Currently have a GoDaddy hosted WordPress site for school. My issue is that when more than three or four students try to login to post on the blog we get a blank screen with ‘no data received’ message. When we try to simply access the homepage the same message appears.
I’ve tried it on a device not connected to the wi-fi and it appears fine. Any idea what is happening as it worked properly when we simply linked to the freebie WordPress blogs?

Thanks for any advice.