Error debugging with two ST link at the same time

[ICohe.1]

Trying to debug with two st link V2 at the same time, I started the first and then tried to start the second. Firstly I had to select the correct serial number for the second ST link but then I got the error: 

Failed to bind to port 61234, error code -1: No error

Failure starting GDB server: TCP port 61234 not available.

Here is the output:

 
STMicroelectronics ST-LINK GDB server. Version 5.5.0
Copyright (c) 2019, STMicroelectronics. All rights reserved.
 
Starting server with the following options:
 Persistent Mode : Disabled
 Logging Level : 1
 Listen Port Number : 61234
 Status Refresh Delay : 15s
 Verbose Mode : Disabled
 SWD Debug : Enabled
 InitWhile : Enabled
 
Failed to bind to port 61234, error code -1: No error
Failure starting GDB server: TCP port 61234 not available.