Is that the exact message?
What version of android are you using?
Check what permissions MusicBee has.
I would clear the app data on the Musicbee app first, do a full sync then try a reverse sync. If that fails then reset GoneMad as well.
That's the exact message as far as what I can see of it (as stated, the display reaches the edge of the screen half-way through what I obviously assume is the word "changed," so if there's more to the error message, I can't see it). I did a Google search for the first part of the phrase and there were only 2 results, both of which led to prior messages within this board's thread.
Android is v.7.0. I don't think permissions would have been reset, I have used all of the involved devices and applications quite recently with no issues up until now. Regardless, I tried clearing the MusicBee sync app data, no luck. I then Cleaned out GoneMad as well (unfortunately, I didn't think to write down or backup all my settings, so that was fun reconfiguring it.

). After redoing everything, I tried the forward sync through the MusicBee wifi app and it worked great. However, the reverse sync is once again giving that same error message.
In addition to forward syncing through the wifi app (again, worked perfect), I've also tried syncing some new songs via my MusicBee program (desktop version, not the app). Twice out of 3 attempts, it stalled and gave an error saying that it failed to sync one of the songs. I also tried syncing just a couple playlists and a window popped up saying "aborted" with an error message stating "Shutdown was already called on this object that owns it. (Exception from HRESULT: 0x802A0002)".
So perhaps the issue is with the main desktop program and not anything on my device? As stated in my prior message, there was a blackout in my building a couple days ago while running the program that crashed my computer (and thus the program as well), so perhaps, that corrupted something? Everything was working fine before that crash and all these problems have arisen immediately following it.
I suppose my next step is to reinstall (unless there's a repair function) the program on my desktop. Can someone please lead me through how to backup both my library (including playcounts, etc.) and the UI interface that I've customized (as well as any sync settings, etc.), assuming all that can be backed up. I think I probably could try and figure it out, but I really don't want to make any mistakes and do anything that accidentally obliterates any data or settings in my library that I've put together over the last couple years of using the program.