Looking at /var/log/auth.log i found this:
Jun 10 20:01:01 host-name CRON[2417]: pam_unix(cron:session): session opened for user forge by (uid=0)
Jun 10 20:01:01 host-name CRON[2417]: pam_unix(cron:session): session closed for user forge
Just at the time I request a "Server test" on Envoyer.io. So, envoyer is using the wrong username to access?