As of November 25th, all emails with a security code are prioritized to go through your account's own SMTP settings, if those settings exist and are valid. NOT through Mobsted's centralized email gateway.
Earlier SMTP was only used for triggered email messages, not for system messages.
Another way to use your own email settings instead of centralized is to add a Mailgun.com account to your Mobsted account settings.
NOTE that if the SMTP password is filled the first attempt is sent using SMTP. If the SMTP attempt fails, then Mobsted will attempt to use your Mailgun account.
As usual - Looking forward to your questions and comments in the Support channels.