This is expected!! The AP will not broadcast or processs more than 16 SSIDs, you need to configure the AP group and then sing this to the AP and then it will work!!
lemme know if this answered ur question and please dont forget to rate the usefull posts!!
the 16 SSID on the AP have been clear.
But I have not defined more the 4 WLAN´s on the WLC
I tried to use on the WLC WLAN id´s above 17 which was not working
Just to elaborate a little on Leolaohoo's post:
APs default to being in the Default-Group (AP Group).
The Default-Group always consists of WLAN 1-16 with the interface mapping on the WLAN config, you cannot change this.
If you define a WLAN #17, you will need to build a new AP Group that contains only the SSIDs you want in that group (up to 16 total, but its ridiculous to put 16 ssids on the same AP). You'll need to set the proper interface mapping when you build the AP group (the wlan default interface mapping has no value here).
Once you have your AP-Group defined, you assign APs to that group (so they are no longer part of Default-Group). I believe this last step will reboot or at least disconnect/reconnect the AP. At this point, your APs should now join the WLC and have only the SSIDs defined in the AP Group.