Conversation so far:
Who was Dawn in relation to Tony Orlando?
Orlando sang under the condition that his name not be associated with the project, so it was released under the simple name of Dawn.
Why did Tony Orlando have a condition about singing with his real name?
He was concerned about a possible conflict of interest with his April-Blackwood duties.
What song did Tony Orlando sing under the name Dawn?
Candida
Was Candida successful for Tony Orlando?
Candida became a worldwide hit, reaching number one in five countries, and the top ten in many others.

Question: was Knock Knock a hit as well?
Self-contained rewrite: Was Knock Knock a hit as well for Tony Orlando?