vip722 hd dvr ota problems

[theone24]

Can anyone help me, my high def locals off my ota antenna was coming in fine through my dish dvr up till 2 days ago and then i just lost the signal for abc cbs nbc anf fox, i've tried re scanning but to no avail. i know the antenna working because took it from the back of the dvr and went straight into my flat screen and all the channels i could not get through the dvr was coming fine through the tv, can anyone tell me what to do thanks