To setup Print To Email for Gmail there are a few additonal steps.
First open MEDILINK32BNT\BIN\MEDILINK.EMAILFILE.EXE
Via SMTP: TICK
SMTP Server: smtp.gmail.com
Sender Email: maybe your gmail address, or maybe a nicer email address if you have set up.
Username: google address (probably gmail)
Password: google password
Click Save Settings.
Now, to test, you need to fill in some of the fields at the top. Browse for a test PDF file and put in a test recipient email address.
You should now click Send Email to test. There is a good chance you will get an error:
"The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required"
Leave MEDILINK.EMAILFILE open, but open your browser and log in to Google.
Navigate to: https://myaccount.google.com/lesssecureapps
Enable Allow less secure apps
Navigate to: https://accounts.google.com/DisplayUnlockCaptcha
Go back to the MEDILINK.EMAILFILE app, and try Send Email now.
If it still doesn't work you may have to go in to the Google Security area and disable additional security measures such as Use your phone to sign in, and 2-Step Verification. Then try again.