I started getting this error earlier this month. March 6 was the last time my tree synched. I'm working on a Mac and enjoyed the tree sync function for about 2 months before it quit working.
FTM 2 tells me I've added 13 people, changed 21. Added 37 citations, 20 media files, and 21 sources.
Every time I attempt to sync I get "The last sync failed. An error occurred while "Uploading changes from Family Tree Maker to Ancestry...". Try again later. If this error recurs, please contact customer support.
I click OK and then FTM2 tells me "Tree was successfully synced" even though it didn't.
It doesn't matter what time of day or day of week. I've tried two different Internet connections.
It would be nice if FTM2 gave an indication what file or bit of data it's tripping up on.