diff --git a/lib/net/imap.rb b/lib/net/imap.rb
index 770e45db7d..39c6734d3b 100644
--- a/lib/net/imap.rb
+++ b/lib/net/imap.rb
@@ -1100,6 +1100,7 @@ module Net
         @tagged_response_arrival = new_cond
         @continued_command_tag = nil
         @continuation_request_arrival = new_cond
+        @continuation_request_exception = nil
         @idle_done_cond = nil
         @logout_command_tag = nil
         @debug_output_bol = true
@@ -1165,7 +1166,8 @@ module Net
               when @logout_command_tag
                 return
               when @continued_command_tag
-                @exception = RESPONSE_ERRORS[resp.name].new(resp)
+                @continuation_request_exception =
+                  RESPONSE_ERRORS[resp.name].new(resp)
                 @continuation_request_arrival.signal
               end
             when UntaggedResponse
@@ -1351,14 +1353,19 @@ module Net
     end
 
     def send_literal(str, tag)
-      put_string("{" + str.bytesize.to_s + "}" + CRLF)
-      @continued_command_tag = tag
-      begin
-        @continuation_request_arrival.wait
-        raise @exception if @exception
-        put_string(str)
-      ensure
-        @continued_command_tag = nil
+      synchronize do
+        put_string("{" + str.bytesize.to_s + "}" + CRLF)
+        @continued_command_tag = tag
+        @continuation_request_exception = nil
+        begin
+          @continuation_request_arrival.wait
+          e = @continuation_request_exception || @exception
+          raise e if e
+          put_string(str)
+        ensure
+          @continued_command_tag = nil
+          @continuation_request_exception = nil
+        end
       end
     end
 
diff --git a/test/net/imap/test_imap.rb b/test/net/imap/test_imap.rb
index 8659622554..5e2dd71c53 100644
--- a/test/net/imap/test_imap.rb
+++ b/test/net/imap/test_imap.rb
@@ -582,7 +582,7 @@ EOF
         received_mail = sock.read(size)
         sock.gets
         sock.print("RUBY0001 OK APPEND completed\r\n")
-        sock.gets
+        requests.push(sock.gets)
         sock.print("* BYE terminating connection\r\n")
         sock.print("RUBY0002 OK LOGOUT completed\r\n")
       ensure
@@ -598,6 +598,8 @@ EOF
       assert_equal("RUBY0001 APPEND INBOX {#{mail.size}}\r\n", requests[0])
       assert_equal(mail, received_mail)
       imap.logout
+      assert_equal(2, requests.length)
+      assert_equal("RUBY0002 LOGOUT\r\n", requests[1])
     ensure
       imap.disconnect if imap
     end
@@ -619,10 +621,9 @@ EOF
       sock = server.accept
       begin
         sock.print("* OK test server\r\n")
-        line = sock.gets
-        requests.push(line)
+        requests.push(sock.gets)
         sock.print("RUBY0001 NO Mailbox doesn't exist\r\n")
-        sock.gets
+        requests.push(sock.gets)
         sock.print("* BYE terminating connection\r\n")
         sock.print("RUBY0002 OK LOGOUT completed\r\n")
       ensure
@@ -639,6 +640,8 @@ EOF
       assert_equal(1, requests.length)
       assert_equal("RUBY0001 APPEND INBOX {#{mail.size}}\r\n", requests[0])
       imap.logout
+      assert_equal(2, requests.length)
+      assert_equal("RUBY0002 LOGOUT\r\n", requests[1])
     ensure
       imap.disconnect if imap
     end