If you're sending a test email from your Gmail account and the target of the email forwarder that you're using is also the same Gmail account, then the forwarded message will not appear in your inbox.
This is based on the way that Gmail handles email threads, and there's no settings or changes that we can make to override that.
If you want to test your email forwarding is working, please send from a different Gmail account to the target email address, or send the test email from another provider.
