I actually had a similar problem with my last Samsung 1-box CCTV kit which was one of the reasons I binned it and bought this one, that and the fact the picture resolution was much lower and it wasn't wireless so I had horrible cables everywhere.
My router is a basic SKY router with minimal settings and I assume my IP address gets automatically changed from time to time which is maybe what has caused my problem as the P2P viewing did work fine initially after first installing the system? The routers can handle heavy traffic (bittorrent /w 100s of connections) but will stop working when browsing casually. There is no indication on what provoces these lock-ups. I'd like to try the devices on a different WiFi network than the DVR is on but during this lockdown I can't get out to log onto another WiFi network anywhere, this still wouldn't actually fix my issue anyway. After a day or so, my internet & network connection will drop all of a sudden and all the routers need a reboot. Unchecked DHCP and Cloud P2P in the DVR settings, applied it then rechecked them and reapplied them (as suggested by the manufactures website).
Uninstalled/reinstalled apps on 3 different devices.And its done Now you have your DVR working with XMEye.
#Xmeye app worked untill i had to restart my wifi code#
choose the date method Enter the captcha code Enter the current date shown in DVR, then click generate code.