Interesting, I have the DS-7604 been working fine since the 25th Feb when I bought it, now can't access it remotely via Hik-Connect. All works perfectly inside my LAN, no network changes, everything else is working fine, just can't access it via the app.
When I log in via the Hik portal it shows it as offline, although on the NVR itself it says it's online... maybe it's a wider problem is there's a few of us suddenly unable to connect?
Any solution yet?