"Error 802.11n SP SSID (already in use)" while configuring wireless

This article applies to SonicWall - Distributed Wireless (SonicPoint configuration from the centralized firewall controller interface)

If a SonicWall firewall running SonicOS Enhanced firmware displays the error "Error: 802.11n SP SSID (already in use)", this normally means that the administrator is training to use an SSID already in use for SonicPoint, and this operation is intentionally avoided by the SonicOS Enhances, and the SonicOS will not allow the SSID to be saved, cancelling the attempt made by the administrator.

However sometimes this error "Error: 802.11n SP SSID (already in use)" may be due to something else.
The below reported figure reports the error after trying to save SSID "Giovanni".

In order to resolve this issue, follow next steps:

1. Double-check if the SSID impacted (SSID that trig the error "Error: 802.11n SP SSID (already in use)") is really in use in the firewall configuration settings of that SonicPoint. If the SSID is in use, then the new SSID is to be different from the one already configured. If this does not resolve the error, then move to step 2;
2. If step 1 does not resolve the issue, then the SSID impacted is written internally and does not get displayed by the SonicOS Enhanced: this may rarely happen after importing SonicOS Settings (.exp file) from a different SonicWall model of firewall. In order to resolve this issue:
   • change the SSID that cannot be edited to any value different from the one that cannot be saved.
   • reboot the appliance
   • edit the impacted SSID to the preferred value: this time the SonicOS will accept the SSID and save it to the configuration settings (exp file).

Example
Scenario: SonicWall Administrator imported settings from a TZ 210 to a NSA 240. In the past on the TZ 210 they configured SSID "Oksana", but then they changed it to "Giovanni". 
The administrator imports the settings from the TZ 210 to the NSA 240 and wants to move back on the NSA the SSID from "Giovanni" to "Oksana", but the SonicOS prevents this change displaying "Error: 802.11n SP SSID (already in use)." 

1. The Administrator verifies that "Oksana" is not currently configured as SSID in the NSA 240 settings (e.g. they have only one SSID "Giovanni");
2. The administrator
   • changes the name of the SSID from "Giovanni" to "Giovanni_NEW";
   • reboot the appliance
   • change the name of the SSID from "Giovanni_NEW" to "Oksana": this time the SonicOS firmware accepts the saving and displays SSID "Oksana". Error is resolved.