"The specified network name is no longer available" exception while reading file over the network

Question

I am using the below code using retry pattern to copy files over the network.

private int ReadSourceStream(FileStream _sourceStream, Byte[] _buffer)
{
    return _sourceStream.Read(_buffer, 0, BUFFER_SIZE);
}

In case the network is disconnected and exception is thrown, the ReadSourceStream is recalled with the same parameters until the network is resumed. The issue is that even after the network is resumed I still get the following exception

The specified network name is no longer available

I added File.Exist check before _sourceStream.Read and it returns true after network is resumed but while reading the stream it throws the exception.

Any of your help in this regard will be highly appreciated.