So I've setup Plex server at home and everytime I try to stream a movie from server to any of my local PCs or Smart TV (wireless or wired), CGN3ACSMR modem crashes and reboots itself (this is my second modem, first one did the same thing). This is so frustrating and i can't figure out why is this happening.
Just looking at the plex site, I can see that it uses SSL and support DLNA. DLNA support is probably pretty common for routers, but I don't know if the modem provides the same support in either or both cases. I suspect if you called into tech support the response would be that SSL and DLNA are beyond Tech Support coverage and you would have to pay $69.95 just to get an answer from the Techxpert staff as to whether or not the modem provides the necessary support. You could always try and see what type of response you get from the first level tech support.
Edit: here's an example of the AsusWRT user interface. If you look at the USB Applications you can see the various settings for media server support. I would think that the modem would require similar settings to run the server correctly.
Edit 2: just looking at the data sheet for the CGN3, it indicates "Integrated DLNA Media Server with support for video, audio and image serving". So, making an assumption here, since the two modems are closely related, the CGN3ACSMR might/should have the same support. If so, does it need enabling by tech support? Looking at the features for the various Hitron modems, DLNA Media Server support is shown for the models listed, including the close cousin, the CGNM-2250, so it should be a safe assumption that the CGN3ACSMR supports this as well.