NVR N800P ask to enter password for each camera after a Aweek.

Dear Sir,
   We are network admin of Thailand. We using your camera for some area which we need to check around because your camera can turn around and cheap price.
The problem what we found as follow.
1) NVR will ask to re-enter password some camera after few days or network restart.
2) NVR can record as normal if they can see all camera but it also don't record on SD car which i put in each camera for sometime.

We use lastest firmware on year 2017. Can you advice how to do?
We did not asking when we connect them to LAN it can record as normally BUT YOU ARE SELLING WIFI camera not wire camera.
Please help us
Appreciate
Best Regards,
Grisree

Hi, Thanks for your message,  I give you the following answer,
1, if the camra password have changed, so you need to change camera password in NVR;
2,For SD card record, please format SD card before recording;