I'll explain the cryptic title in a moment. We're using MikroTik Cubes to form a studio-to-transmitter link for our community radio station. Analog audio is fed into a Barix Instreamer at the studio which converts it to a digital stream which is fed to the Cube on the roof, which in turn beams to the transmitter site across a parking lot. On that side, the process is reversed and analog audio is fed to the transmitter. At the studio we're using a simple router that manages connections, but is not connected to an outside network.

The MikroTik units have been like absolute rocks, working 24/7, even through hurricane force winds! Last week, though, we lost audio to the transmitter. I could log into the studio-side Cube without problem, and could "see" and log into the transmitter-side unit. Signal strengths were solid.

But, when I went to the transmitter, I could not log into its Cube. Apparently the POE unit was functioning, but there was no data passing through and I could not see (or ping) either of the Barix units. It's like we have a bridge, but it's half a bridge!

I'm an audio guy stumbling my way through IT stuff (not to mention, I'm an old dude so climbing on rooftops is literally a pain). My thoughts on troubleshooting: maybe the Ethernet cable to the roof at the transmitter has a fault whereby POE passes, but data doesn't. Or, maybe there's something wacky about the router. I would welcome some additional thoughts; Monday I'll haul my aging carcass to the roof of the transmitter building to "ring out" the Ethernet cable.

Only hurricane winds or heavy rain too?

JFYI, issues with water have been reported several times:
viewtopic.php?t=189614

Mikrotik discontinued quite some of its very usefull trouble shooting hardware.
Like give an MQS to your audio guy, to attach it to the Cube.
https://mikrotik.com/product/mqs

Maybe some stores still have it. (RBMQS, check LinITX?)