altyron

I have a 3 x camera Swann 1080p setup. Installed February 2016. When I click to open the system on my PC or smartphone I get a mainly blank screen. The wee NVR icon has a red cross or red question mark on it. All device lights look ok. I've switched the NVR box off and back on again in case this might help. I can't PREVIEW or PLAYBACK. This happened once before and it miraculously self corrected the next day. Is there a known fault? Has anybody had this joyous experience? Thanks, Ronnie