While trying to resume a previously broken upload, it seems that the FTP server do not support download and upload resuming.
When the NAS-R3 Ent. FTP server receive the APPE command (Used to resume a transfer), the server reply that the Append and Restart commands are not permitted...
Just tested this as well on the 4.12 version and this seems to work when downloading (tested by breaking connection then reconnected and started to resume again) but not uploading. Again waiting for the new version to find out. Forgot, this was without Encryption settings: SSL/TLS new setting added is "none". Also tested this WS_FTP.
Mathieu, I see you have received DSS and this was not a mistake . We will be working on a release to have some of the FTP issues resolved. Please test and let us know after the 15th when the release is out to test. Thanks again for helping our support team as we are so very busy. You will really appreciate DSS