Gmail is popular by many means, so I have been using Gmail to receive scans from my Brother scanner/printer (MFC6890CDW). Somewhere in 2014 Gmail went to receiving Email encrypted only (using SSL). However, the printer does not support SSL when sending email, it expects a plain SMTP server to listen. There is no elegant way to solve this, so here is what I did: I used a RaspberryPi, which is running some other software for me, as a server to run stunnel4 – s(ecure)tunnel) – which wraps the connection from my sanner to Gmail into SSL. Here are the instructions that worked for me:

1. Log in to your RaspberryPi and update your packages lists by using:
   sudo apt-get update
2. Install stunnel4 using
   sudo apt-get install stunnel4
3. Configure file /etc/stunnel/stunnel.conf, and add the following (one) line at the end of it:
   [SMTP Gmail]
client = yes
accept = 0.0.0.0:25
connect = smtp.gmail.com:465
4. Generate stunnel.pem key (needed for the encryption) and copying to the desired place by using:
   cd /etc/stunnel/
sudo openssl genrsa -out key.pem 2048
sudo openssl req -new -x509 -key key.pem -out cert.pem -days 1095
sudo su
cat key.pem cert.pem > /etc/stunnel/stunnel.pem
exit
cp /etc/stunnel/stunnel.pem /etc/ssl/certs

Note that this key runs out after 1095 days, so you need to revisit that at some point.

1. Configuring (a Brother in this case) printer via ControlCenter3: Start ControlCenter3 -> device settings -> remote setup (standard password „access“) -> server settings -> SMTP server -> IP address (that is the IP address of the machine running stunnel) -> SMTP port 25 -> account name „your.name@gmail.com“ -> Account password -> „Your Password“
2. Start stunnel using /etc/init.d/stunnel start

That did it for me! Good luck!