Same issue here. I recently upgraded my Linux server and clients and got resilio sync updated to 2.5.2. My desktop/server clients are not able to see each other. The strange thing is, that my iPhone sees both of them (at the same time) and they see my iPhone, but they can't see each other. Tried it with two Windows clients. Both were 2.4.5. initially and they were able to see (and sync with) ONE (not the other) 2.5.2 linux machine. I updated one of the Windows machines to 2.5.2.. after that it is not able to see my 2.5.2 Linux machines, but my other 2.4.5 Windows machine is still there. The last "we are working on this" reply is from 05/12/17.. Can we expect a fix for this (aside downgrading) till Monday? I really require sync during the week to work as I expect it to. I'm already thinking of switching to another service, breaking sync functionality during a update is just a No-Go.