Error with uploading almost large files

Hello there
I have an own deployed parse server but there are some issues with that.

First things first, I can not upload files larger than 1 or 2 MB from android client and any other clients. The progress callback says that uploading is done, I mean it gives me the 100 percent, but the save callback is called with exception after a few unsuccessful tries, throwing I/O failure. The weird thing is that, if I use a fast network, for example a 4G cellular data, everything is fine! The save call back comes up with no error and the file will be uploaded.

Second, I can stream any video from any server in my android client, but not my own server. I mean when I try to stream a video from my own server, the video player shows -2147483648 error.

I should point that my server’s hardware is not that powerful and all client functionalities are tested on Back4app.com server. Finally, is there anyone who has faced these sort of issues on an own deployed parse server? And may you tell me if I can fix things with server side code or I should use a more powerful server?