Why doesn't bandwidth go into these zones?

This is essentially a dup of another approved post:

I’m moving the rest of the questions there!

I have run fiber into the zones. The fiber have full bandwidth.
I’ve run a star of cables, which mostly seem to have full bandwidth.
Yet the zones keep blinking in and out of connection.
Also, one of the cables keep draining/refilling, whereas the other cables in the same zone just stay filled up.

(moved content)