404 errors when uploading PDF locally with Docker

[Allaman]

Hello,

I try to get this running and get 404 when uploading manual (I don't have a RM account)

What have I done:

docker build .  --progress plain -t remarkableweb
docker run --rm -d -p 3000:3000 --name remarkableweb remarkableweb

Access the service with Firefox at localhost:3000. Click If you wish to upload a PDF manually, click here. Drag and drop a pdf (size 1.3M) that I exported via mail from my RM2 (1.14)

Thanks for any hints!

PS: I would prefer to not have to run npm natively on my machine :)