at first many thanks for the great DL Service and the Thunderbird AddOn. I set this up weeks ago and it worked perfect (I never used Filelink before because of security consideration; DL was easy to install on our managed server).
Now we upgraded Thunderbird to version 38.0.1 and nothing is uploaded. The filelink is offered but when I am using it the busy sign beneath the attachment filename is shown for an unlimited time.
This review is for a previous version of the add-on (0.13).
If you could report the issue to the main tracker here https://github.com/wavexx/dl/issues (in order not to lose track) it would be great. Reviews are not really meant to troubleshoot problems. That being said, we'll look into that, but please followup the discussion on github.
Update: The version 0.17 fixes this issue and is currently under review. If you don't want to wait, you can see the new versions of the addon under "View other versions" next to the download link.