John wrote:

I've made the change to force HTTP 1.1 and this will go out with Dropzone 4.0.9. I'm pretty optimistic this will resolve it.

I'll look forward to v4.0.9, and thank you!

John wrote:

Are you using a proxy? The Imgur action doesn't support proxies currently.

Nope, not to my knowledge.  Does the log imply that?

I used to use Dropzone with Imgur uploads all the time, but for a long time now it has just stopped working.  The issue is the upload hangs at various points as if there were a protocol timeout (it's not always at the same point during progress).

I don't think it's my computer (Apple 2019 MBP) or my OS (macOS Catalina, fully patched) or my provider (100 Mbps down, 35 Mbps up) as I always end up just using the native Imgur web interface immediately afterward and it works with no problem.

I can't say exactly when this started, although I think it was toward the end of Dropzone 3, and it has continued with Dropzone 4 to the present day.

Here is a pic of the UI during a "timeout":

UI

And here is a pic of the logfile:

logfile

Any ideas?