Five Netvue cameras offline

Since September 12, 2022; All five of my netvue cameras at my business say OFFLINE and can’t view thru them from offsite. I did all the suggested processes of rebooting cams, rebooting router, put cams right by router, removed and reattached antennae, removed and reinserted SD card,etc. Nothing corrects the problem.

This happened in June for about 2 weeks and they mysteriously came back on with no action on my part. The cameras have been operating fine with no problems up to June and with no changed to anything on my end. Then they were down for 2 weeks and came back up–with no changes on my end. They worked fine from that time in June thru September 12–then went down September 12 and none have come back up.

They are defined to the network and viewable at times when on their network. However, when trying to view from outside the network, they all say they are offline.

Firmware is 1785 and network provider is AT&T.

Any help please?