How could I fix these Nextcloud warnings?

* Your web server is not yet properly set up to allow file synchronization, because the WebDAV interface seems to be broken.

* Your web server is not properly set up to resolve "/.well-known/caldav". Further information can be found in the [documentation ↗](https://docs.nextcloud.com/server/27/go.php?to=admin-setup-well-known-URL).
* Your web server is not properly set up to resolve "/.well-known/carddav". Further information can be found in the [documentation ↗](https://docs.nextcloud.com/server/27/go.php?to=admin-setup-well-known-URL).
* You have not set or verified your email server configuration, yet. Please head over to the [Basic settings](https://nextcloud.shaniag.com/settings/admin) in order to set them. Afterwards, use the "Send email" button below the form to verify your settings.
* The PHP OPcache module is not properly configured. See the [documentation ↗](https://docs.nextcloud.com/server/27/go.php?to=admin-php-opcache) for more information.
  * The OPcache interned strings buffer is nearly full. To assure that repeating strings can be effectively cached, it is recommended to apply `opcache.interned_strings_buffer` to your PHP configuration with a value higher than `8`.

Here is my configuration for reference:

nextcloud = {
      enable = true;
      package = pkgs.nextcloud27;
      hostName = "nextcloud.shaniag.com";
      database.createLocally = true;
      https = true;
      configureRedis = true;
      config = {
        dbtype = "pgsql";
        adminuser = "shaniag";
        adminpassFile = "/var/run/nextcloud-pass.txt";
        defaultPhoneRegion = "EN";
      };
      extraOptions = {
        mail_smtpmode = "sendmail";
        mail_sendmailmode = "pipe";
      };
      autoUpdateApps.enable = true;
    };
  };