Cannot upload certificate files

[Grekkor]

I cannot upload certificate files,
It just does nothing and then says: "Upload failed: 0"

[jc21]

Anything in the docker logs?

[Grekkor]

Only:

Connection Error: Error: Connection lost: The server closed the connection.

I generated the certificate files on linux. I got two .pem files.
I tried uploading them as .crt and .key files aswell but no luck.
Here the command I used:
openssl req -x509 -newkey rsa:4096 -keyout HomeCertificateKey.pem -out HomeCertificateCert.pem -days 365

Edit: Nvm, the docker log entry has nothing to do with this issue in my opinion. I just tested it again and nothing new appears in the log.
Edit 2: When trying to upload .txt files then I get:

Upload failed: 400

and a log entry:
[1/14/2019] [6:53:05 AM] [Express ] › ⚠ warning Certificate is not valid (Command failed: openssl x509 -in /tmp/6cba1486-d794-45ef-8e21-397f1df69b6d/tmp -subject -noout unable to load certificate 140095325644032:error:0906D06C:PEM routines:PEM_read_bio:no start line:../crypto/pem/pem_lib.c:691:Expecting: TRUSTED CERTIFICATE)
Hence my assumption is it has to do with certificate validation, which is maybe stuck in an infinite loop? It takes like a good 1-2 minutes before the error notification appears. The 400 error appears instantaneously.

Edit 3: The upload succeeds when using the -nodes option to disable DES. I now used the following command:
openssl req -newkey rsa:4096 -nodes -keyout HomeCertificateKey.pem -x509 -days 365 -out HomeCertificateCert.pem
I suggest you either support DES or document somewhere the constraints on the certificates.

[chaptergy]

This issue should be fixed, certificate upload is currently working.