Não está enviando email [ Process exited with a non-zero status]

Boa noite, está acontecendo o seguinte erro ao enviar email:

thiagonasper@meupc:~$ mail --config-verbose -s "Hello World" thiagonasper@gmail.com <<< 'This is a message'
mail: opening configuration file /etc/mailutils.conf
mail: configuration file /etc/mailutils.conf doesn't exist
mail: opening configuration file /home/thiagonasper/.mail
mail: configuration file /home/thiagonasper/.mail doesn't exist
mail: cannot send message: Process exited with a non-zero status

Meu arquivo /etc/ssmtp/ssmtp.conf é:

root=meuemail@gmail.com
mailhub=smtp.gmail.com:587
hostname=meupc
AuthUser=meuemail@gmail.com
AuthPass=minhasenha
UseSTARTTLS=yes
UseTLS=yes