I would be very interested to find out if these problems can be resolved or explained. I tried using DigitalOcean - it worked fine for single upload, but not for multiple. Using the same API file, and the same App Connect file, with ‘Single’ selected it worked, with ‘Multi’ it failed. I would have thought this meant everything was set up correctly, but no solution was found and I gave up.
In case there’s anything which might help with your particular case, here is the thread.