Website Authentication Fail

Hi, when users go to https://www.dialogueafrica.com (which is my website), they get the following error message: The page at https://dialogueafrica.com says: Authentication Fail. What does this mean? I have disabled all the plugins to see if that was the cause but the error message has persisted. This only started a few days ago. I’m using a customized version of the Sparkle magazine theme. My host support seems to think the theme requires some sort of authentication. But I’m not sure how to disable that. Please help?