A link that worked and then stopped usually means something physical changed between the two ends. Transporters parked in a new spot, a new building, a crowd where there was open ground, or the antenna knocked out of aim.
Work outward from the tower:
- Is the antenna still outside, still pointed the right way, still connected?
- Has anything large appeared in the line of sight?
- Is the far end powered and awake?
For a long or obstructed path, a directional flat panel antenna aimed down the track will hold a link that an omnidirectional antenna cannot.
Systems built for redundancy handle this differently: with both a hardwired network and a wireless controller live at once, losing the wireless path does not stop the event, which is the entire argument for that configuration on a professional program.