Tell user if mail can't be sent after install

Hello. I have set up ghost on DigitalOcean, it went very well and all is smooth… but I realised quite late that I can’t send emails from my DO droplet, as DO blocks port 25 by default. It works fine with an external SMTP like mailgun.
However, until I had set up Mailgun, it meant that Ghost couldn’t send me an email, for instance to recover my password. This is a big issue as I wasn’t told about that.
If I missed a message during the install process, my apologies, but otherwise, could the Ghost install say if sending an email doesn’t work?
Or something like “Ghost is installed, we’ve sent you an email, if you don’t receive it you may need to set up Mailgun as per instructions here”.
Or flagging this in the post-install instructions for the One-Click App on DO?