config:

mail_attribute_dict = file:%h/dovecot-attributes
mailbox_list_index=yes
plugin {
        push_notification_driver = dlog
        push_notification_driver = ox:url=http://127.0.0.1:80/notify-example.php
}
protocol imap {
    mail_plugins = autocreate notify push_notification
    imap_metadata = yes
}
protocol lda {
    mail_plugins = autocreate notify push_notification
    log_path = /var/log/lda.log
}
Error:
Debug: push-notification-ox: Skipped because not active (/private/vendor/vendor.dovecot/pvt/server/vendor/vendor.dovecot/http-notify METADATA not set)