i've insalled owncloud 9.1.4 on my hosting service provider, al works fine with no errors but when i use desktop client for sync none of files where sync.
it correctly create folders but no file inside.
the error for all is "server did not acknowledge the last chunk. (No e-tag were present)"
Most likely a misconfiguration on server side. The following FAQs [1] and [2] might help to debug your issue. Especially [2] has a part about "No E-Tag" there.
Also quoting from an existing thread in [3] which pops up in the search of the forums:
Unfortunately this is a "catchall" error which can have tons of solutions so you probably need to dig your way through google or the github issue tracker [1] for the message The server did not acknowledge the last chunk. (No e-tag was present) to find a solution matching your problem.
so yes. Most likely caused by some security module or security configuration within your webserver. Maybe try to contact the support of your hoster and point them to the links above. They might know whats wrong in their environment.