diff --git a/src/main/java/net/schmizz/sshj/connection/channel/ChannelOutputStream.java b/src/main/java/net/schmizz/sshj/connection/channel/ChannelOutputStream.java
index 0695d0b8..ad30493f 100644
--- a/src/main/java/net/schmizz/sshj/connection/channel/ChannelOutputStream.java
+++ b/src/main/java/net/schmizz/sshj/connection/channel/ChannelOutputStream.java
@@ -150,7 +150,8 @@ public final class ChannelOutputStream extends OutputStream implements ErrorNoti
     }
 
     private void checkClose() throws SSHException {
-        if (closed) {
+        // Check whether either the Stream is closed, or the underlying channel is closed
+        if (closed || !chan.isOpen()) {
             if (error != null)
                 throw error;
             else
@@ -160,7 +161,8 @@ public final class ChannelOutputStream extends OutputStream implements ErrorNoti
 
     @Override
     public synchronized void close() throws IOException {
-        if (!closed) {
+        // Not closed yet, and underlying channel is open to flush the data to.
+        if (!closed && chan.isOpen()) {
             try {
                 buffer.flush(false);
 //                trans.write(new SSHPacket(Message.CHANNEL_EOF).putUInt32(chan.getRecipient()));