Updating nextcloud

Dear Community,
Today I tried to update my Nextcloud from 16.0.1 to 16.0.6.

On the update page I get this text:

There are some errors regarding your setup.

* Error occurred while checking server setup

* The "Strict-Transport-Security" HTTP header is not set to at least "15552000" seconds. For enhanced security, it is recommended to enable HSTS as described in the [security tips ↗](https://docs.nextcloud.com/server/16/go.php?to=admin-security).

How to resolve this?

When clicking on “run updater now” I get this message: “php -r ‘$password = trim(shell_exec(“openssl rand -base64 48”));if(strlen($password) === 64) {$hash = password_hash($password, PASSWORD_DEFAULT) . “\n”; echo "Insert as “updater.secret”: ".$hash; echo “The plaintext value is: “.$password.”\n”;}else{echo “Could not execute OpenSSL.\n”;};’”

When opening my config.php file i can find updater.secret but it is not working!

What am i doing wrong?

Thank you!