Also add reminder to 6.7.2

6-asyn-troubleshooting.md

@@ -146,6 +146,8 @@ Type `ctrl+c` in the xterm window or click the `X` in the corner of the window.
 
 #### 6.7.2 Run server-new-fw.py
 
+Reminder: the port argument passed to the `-p` option must match the value of `VMC_PORT` chosen in [step 5.7.2](5-Add-virtual-motors.md#572-modify-iocshvmccmd)
+
 ```
 $ xterm -e "${SUPPORT_DIR}/motorVMC/python/server-new-fw.py -p 33333" &
 ```