WizFi310 open socket "server mode" (TSN) returns invalid parameter

[JMRib]

Hi

We are developing a new product with a WizFi310 device. I’m trying to open a “TCP SERVER normal” socket using:

AT+SCON=O,TSN,,,2330

and always returns:

[ERROR: INVALID INPUT]

What could be the problem?

Thank you

[JMRib]

Resolved! The socket listener was already opened…