Good advice here already… get a tester. And put your box in a damp spot, or where you can dump water on the ground around it often.
I do not have “electrobraid”, but I do have other types of “tape” with small wires running through it to carry the charge. I bought that because I wanted it to be SEEN. But what I found was that the tiny wires running through the several different types of tape tended to “work” back and forth in the wind and with time and use, and the tape went dead. And it can’t be “fixed”, it has to be replaced. Because you have no idea where the tiny wires running through the tape are broken (the “working” back and forth in the wind etc breaks the tiny wires??? I’m guessing). So, I no longer use that sort of stuff. I have not used “Electrobraid”, but I’m presuming that it works on a similar plan. If not, feel free to ignore this advice.
I use electric wire only now. Either aluminum wire, or the steel wire… doesn’t matter. Once stung once, the horses know it’s there, and avoid it like the plague. If it breaks (and it does if a deer gets tangled up in it, or other ???), the break is easy to find if you walk the fenceline, and easily fixed, either by adding a new piece of wire, or simply reattaching the broken ends. With the other stuff, you have to replace it ALL, because the breaks are EVERYWHERE and/or tiny, so you can’t simply splice a new piece in. If your electrobraid is OLD, it may simply be worn out, full of breaks everywhere in the wire that carries the charge. If it’s new, you must have a different problem. If you want to keep the “visual” of the Electrobraid, whether or not it’s working, you could consider simply adding a metal wire which runs through the same insulators, and will carry the charge.