.Net Core Process.Start on Linux

I am facing the following issue when running my .Net Core application on Linux.

Here is the exception:

System.ComponentModel.Win32Exception (0x80004005): Permission denied
   at Interop.Sys.ForkAndExecProcess(String filename, String[] argv, String[] envp, String cwd, Boolean redirectStdin, Boolean redirectStdout, Boolean redirectStderr, Int32& lpChildPid, Int32& stdinFd, Int32& stdoutFd, Int32& stderrFd)
   at System.Diagnostics.Process.StartCore(ProcessStartInfo startInfo)
   at System.Diagnostics.Process.Start()
   at Ombi.Schedule.Jobs.Ombi.OmbiAutomaticUpdater.<Update>d__18.MoveNext() in C:\projects\requestplex\src\Ombi.Schedule\Jobs\Ombi\OmbiAutomaticUpdater.cs:line 218

Here is the code:

var updaterFile = Path.Combine(Path.GetDirectoryName(Assembly.GetEntryAssembly().Location),
     "TempUpdate", $"Ombi.Updater");

var start = new ProcessStartInfo
{
    UseShellExecute = false,
    CreateNoWindow = true,
    FileName = updaterFile,
    Arguments = GetArgs(settings), // This just gets some command line arguments for the app i am attempting to launch
    WorkingDirectory = Path.Combine(Path.GetDirectoryName(Assembly.GetEntryAssembly().Location), "TempUpdate"),
};

using (var proc = new Process { StartInfo = start })
{
    proc.Start();
}

It seems that the exception is being thrown when we call .Start().

I am not sure why this is happening, the permissions on the file and folders have been set to 777.