Cache:clear PROD-env ERROR


Pimcore v. 5.2.3

When I clear the cache in PROD-env using bin/console cache:clear or Admin-interface I get the following error:

PHP Fatal error: Uncaught Symfony\Component\Debug\Exception\FatalThrowableError: Parse error: syntax error, unexpected ‘?’, expecting variable (T_VARIABLE) in /applications/http/var/cache/prod/ContainerWrjixkh/Navigation_a34f8f7.php:15

BUT, clearing the cache is working fine in DEV-env.

I don’t know what the problem is!
Any help please!?