I am attempting to setup so I can mail from Raspbian.When I attempt to send I get an error ssmtp: Cannot open smtp.gmail.com:587 (I also tried port:465)I have set Access for less secure apps on Google and can send/receive from the account on Thunderbird.I have installed ssmtp and configured /etc/ssmtp/ssmtp.conf to contain:-# Config file for sSMTP sendmail## The person who gets all mail for userids < 1000# Make this empty to disable rewriting.root=xxxxxx.raspberry.pi@gmail.com# The place where the mail goes. The actual machine name is required no # MX records are consulted. Commonly mailhosts are named mail.domain.commailhub=smtp.gmail.com:587AuthUser=xxxxxx.raspberry.pi@gmail.comAuthPass=xxxxxxxxxxxxxxUseTLS=YESUseSTARTTLS=YES# Where will the mail seem to come from?rewriteDomain=gmail.com# The full hostnamehostname=xxxxxx.raspberry.pi@gmail.com# Are users allowed to set their own From: address?# YES - Allow the user to specify their own From: address# NO - Use the system generated From: addressFromLineOverride=YESI have also configured /etc/ssmtp/revaliases to contain:-# sSMTP aliases# # Format:   local_account:outgoing_address:mailhub## Example: root:your_login@your.domain:mailhub.your.domain[:port]# where [:port] is an optional port number that defaults to 25.root:xxxxxx.raspberry.pi@gmail.com:smtp.gmail.com:587Any suggestions?EditThe settings above based on  https://wiki.archlinux.org/index.php/SSMTPI have done some further testing.I selected a different SMTP server, which worked. (I do not want to use this, as it is only available when directly connected to my ISP.)I tried setting an Application Specific password, and got the responseThe setting you are looking for is not available for your account. (Presumably because this account does not have 2-factor authentication.)The gmail account I am trying to use was specifically created to send messages from the Raspberry Pi.
Problem sending to gmail using ssmtp
ssmtp
The hostname assignment looks wrong. You probably want hostname=raspberry.pi or something like that. (Ideally, your host has a public DNS name, and you should use that.)  It should not be an email address.