kein Zugang >> no access --- kein Zutritt >> no entry

"Kein Zugang" means you can not access or reach a certain target this way - but it does not imply that it is forbidden for you to go there.

"Kein Zutritt" means it is forbidden.

"Kein Zugang zum Messegelände" means: you cannot reach the Messegelände on this way. "Kein Zutritt zum Messegelände" mean: you could reach the Messegelände on this way, but you are not allowed to.

• kein Zugang – no access
• kein Zutritt – no entry

Kein Zugang means you can not access or reach a certain target this way – but it does not imply that it is forbidden for you to go there.

Kein Zutritt means it is forbidden.

Kein Zugang zum Messegelände

means: you cannot reach the Messegelände on this way.

Kein Zutritt zum Messegelände

means: you could reach the Messegelände on this way, but you are not allowed to.