I'm running Ubuntu Server 16.04 with the ssmtp package for sendmail. I've read from a variety of places that you cannot use "special" characters in the password, and I've discovered it's true that I cannot escape nor quote the password. I have only been able to verify alphanumeric passwords in ssmtp.conf to work, but I cannot find this documented anywhere. My question is, what are the allowed/forbidden characters for a password?
Alternatively, is there any other method of escaping? I've tried backslash, single, and double quotes to no avail.