Coincides

The pronouns are a bit confusing.

He needs to talk to the professor, but his office hours coincide with the man's classes.

Thank you so much .Then the verb coincide is proper in this context.

"Coincides" is misspelled.

It's risky business to use "his" to refer to two different people in the same clause.
You make us work too hard to figure out who's who. Presumably, "the man" is the professor's student, but you don't exactly make that clear. Maybe he's the student's father.

You need the plural verb: ". . . . office hours coincide with etc."

Try a

Thank you for your accuracy. At first coincide was misspelled but later I rectified my mistake.

The man needs to ta

All we need now is to move the apostrophe back one letter.

Edit. "Clash" seems a little too violent for th

Thank you very much. His class clashes with the professor's office hours.

Then, neither clash nor coincide is proper.

Or 'conflicts'.

Ah, great minds!

Is my sentence proper? His class conflicts with the professor's office hours.

I believe you need, "His classes conflict with the professor's office hours."