Can't do preauth

[Moudar]

Hi 

On my 5520 WLC running  8.10.190.0, I am seeing this log so much with so many different clients, here is an example:

*apfMsConnTask_6: Jan 23 14:21:03.780: %APF-3-PREAUTH_FAILURE: [SA]apf_80211.c:15788  There is no PMK cache entry for client50:28:4a:ce:84:16. Can't do preauth

 Do I have a problem with Roaming? This log is coming all the time ! 

I don't have complains but wonder why is this happening?! 

[MHM Cisco World]

PMK is one of key in 4 handshake between AP and wifi client'

So sure there is AP or client dont support this 4 handshake.

Can I see l2 secuirty of wlan 

MHM

[Moudar]

So, what does mean if about 90% of logs on the WLC are about the same thing, but about different users!

Do I need to fix something?