I made the mistake to completely uninstall and reinstall the maxthon 5. After login the synchronization started and then failed. The downloaded favorites are about a half year old, most of the favorite folders are empty, duplicates, old deleted links. I suspect that the problem was generated when I tried first time the version 6. Since then, the version 5 did not synchronize, the abnormal account error was from about a month. Now version 5 fails also to synchronize, the sync favorites rotating icon don't stop or stop with an error message.
[update] I made the Windows 10 system restore and to my surprise the Maxthon 5 and its data was restored and now is working and in sync.