Generally, when the app fails at 85%, this indicates the either the IP Camera / DVR / NVR is offline, or an issue with a setting at the connected router.
1) I would recommend switching to the opposite network on your phone. If you're using your local WIFI connection, switch to 4G/LTE or vice versa.
2) If the issue still continues, I would recommend rebooting the DVR / NVR system and router, by removing the power connection for 30 seconds or more, and then plugging the power connection back in and letting the DVR / NVR boot up. Once the DVR / NVR boots up, please access the DVR / NVR's Network menu as seen here:
On the Network page, ensure that the "Obtain an IP Address Automatically" option is enabled, and that there is no information in the Username or Password fields, then select Test.
If you get an "OK" message, please try connecting to the app.
If the IP Camera / DVR / NVR is online, the issue will be with the DHCP setting on the router. In order for the app to locate the IP Camera / DVR / NVR on your network, the DHCP setting on the router needs to be enabled, the firewall on the router needs to be closed.