Okay, I followed Steven's advice. I cleared the application data for the app and re-ran the app and this worked. One thing I just learned- uninstalling an Android app doesn't appear to clear the all app data. I thought uninstalling an Android app deleted all associated data. Before this, I uninstalled and reinstalled a few times and noticed that the error log still had entries from last week even after uninstalling and reinstalling.
So I think what happened is my WIFI router is a DHCP server and is configured for 1 week leases (I don't have access to it but this is my guess). The IP address on either the phone or computer changed but perhaps the app was still looking for the old address? When I looked at the old log there were entries referencing the old address of 192.168.1.13 and the current computer address was 192.168.1.10. Clearing the data worked.
Next, I tried a Reverse Sync to computer. Here is the test:
1. I rated a track in GoneMad.
2. I exported a stats.xml file using the 'Backup Stats function' (going to : gmmp\stats.xml).
3. I opened the stats.xml file on my computer and verified that the song I rated is there:
4. I verified that MusicBee does not have this track rated in the database.
Result: It takes a while as it scans though the files but it returns "No changes detected".
Looking in the wifi sync log, I can see it setting up the paths correctly, it counts the correct number of files, communicates with the server, ratings=true, etc. I don't see any errors.
On the other hand, when I do the reverse test- 'Sync from computer' it is very reliable and seems to always work as expected, all tracks that were rated or played in MusicBee are copied over to the phone. I have tested this several times and it always seems to work.
Is the Reverse Sync to computer working yet? This last function is like the holy grail for me. I have been missing this feature since I abandoned itunes and my 3rd gen ipod 8 years ago. This is an exciting project. Thank you Steven for your awesome software development efforts.