Does the following passage contain a colon error?

Becoming famous was surprising to him: because he’d always thought of himself as just a regular person and not a gifted writer.

No, the passage does not contain a colon error. The colon is used correctly to introduce an explanation or elaboration after the statement "Becoming famous was surprising to him."

No, the passage does not contain a colon error. The colon is correctly used to introduce an explanation or elaboration of the first part of the sentence.