trouble with large files

[aklferris]

Can someone help me with this issue? I am unable to upload 5.5GB .iso despite the following:
max upload size set to 7GB (verified in webgui)
max memory usage set to 1GB (verified in webgui)
small files (e.g. screenshots) work fine in sharex
file is failing in sharex and through the website uploader
vps is running nginx proxy manager w/ valid cert

Racknerd VPS being used
3.5GB RAM
2vCPU
80GB SSD space
20TB transfer

sharex error msg:

Error message:
Unable to write data to the transport connection: An existing connection was forcibly closed by the remote host.

Request URL:
https://files.[redacted].com/upload

Stack trace:
at System.Net.Sockets.NetworkStream.Write(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.Security._SslStream.StartWriting(Byte[] buffer, Int32 offset, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security._SslStream.ProcessWrite(Byte[] buffer, Int32 offset, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.PooledStream.Write(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.ConnectStream.InternalWrite(Boolean async, Byte[] buffer, Int32 offset, Int32 size, AsyncCallback callback, Object state)
at System.Net.ConnectStream.Write(Byte[] buffer, Int32 offset, Int32 size)
at ShareX.UploadersLib.Uploader.TransferData(Stream dataStream, Stream requestStream, Int64 dataPosition, Int64 dataLength)
at ShareX.UploadersLib.Uploader.SendRequestFile(String url, Stream data, String fileName, String fileFormName, Dictionary`2 args, NameValueCollection headers, CookieCollection cookies, HttpMethod method, String contentType, String relatedData)