I’ve had AnkiDroid for about a month. It synced without problems the first few times. For the past couple of weeks, it never actually starts syncing. The sync dialog shows Preparing syncing…Up: 0 KB, down: KB for a long time, then it just exits back to the app.
I tried Check Database and deleted the unused media. The last time I tried to sync, I saw an error about a possibly large media file in my collection. The largest media file in my collection is about 45 MBs.