DVR and SMTP

I have a EMG2926 videotron router. I've installed a small camera setup at home (Bunker Hill Security DVR #61229). On the local network, all is good. DVR has his static IP (I can choose it), and video stream goeas through the port of my choosing (3001, as recommended by the manufacturer). I even can remote access the system using my cellphone if I am on the local network.

However, when I am not on the local network, it gets trickier : I cannot acces my DVR. I think the problem is about some in or out blocked port. (I did find a sketchy solution consisting of remote acces on the local network using a computer, and then remote acces this computer from the outside, but that's not ideal)

Another thing is email alerts. The DVR system can, when properly configurated, send alerts by email when motion is detected. I configured as instructed by the manufacturer to send email using the gmai lsmtp server (through 465 or 587 port). Once again, this does not work, I get an authentification error. And once again, I thing it has something to do with blocked port.

So if anyone has any ideas, I'm open to suggestions !