Hi,
Please try to verify the config use the following DOC as an Example(i suppose you are using SSL):
http://www.cisco.com/c/en/us/support/docs/routers/3800-series-integrated-services-routers/110608-ssl-ios-00.html
If possible please share your configuration.
Note : AnyConnect Uses SSL and IKEv2 as Client VPN protocol, these doesn't have pre-shared authentication.
https://supportforums.cisco.com/discussion/12237241/anyconnect-ikev2-psk-pre-shared-key-possible-under-ikev1-cisco-vpn-client
Regards
Jagmeet