DVR stopped working after factory reset

[jrzus 0]

Hi guys I am new to this board. I have been using Swann DVR, with 6 different brand ip cameras for 4 years now and never had any problem, recently one of the cameras stopped working so I changed it to the original swann brand but while doing so I reset the DVR to factory reset and now all 5 cameras of different brands stopped, showing video loss and the original new swann camera works fine, Please advise