I used to have a gmail account that was a convenient alias. It was set up to automatically forward mail it received to a special email address for that purpose at my own SMTP server. For example, people would send to firstname.lastname@example.org, and that mail would automatically go to email@example.com. I only logged into the gmail account for administration purposes, and received all the mail via firstname.lastname@example.org. Everything worked as I wanted it to.
However, last year Google made some change saying I needed to convert my gmail account to a "Google account". Unfortunately, that was very poorly defined, and it was not clear at all what that really meant, but it seemed the existing gmail account was going to go away. So, I converted as asked.
Now email sent to email@example.com gets stuck there. I can see it if I log in, but I don't want to. I went thru all (I think) menus and settings, but didn't find anything that looked like a way to tell it to forward or copy mail to some external address. There is a way to "add" a mail address, but that seems to be for aliasing the From: field, not for automatic forwarding.
How do I set up a Google account to automatically forward mail to a different non-Google email address?