AP mode not working

[mintu19]

I try

pi@raspberry:~$ sudo hostapd /etc/hostapd/hostapd.conf
Configuration file: /etc/hostapd/hostapd.conf
nl80211: Could not configure driver mode
nl80211: deinit ifname=wlan0 disabled_11b_rates=0
nl80211 driver initialization failed.
wlan0: interface state UNINITIALIZED->DISABLED
wlan0: AP-DISABLED
hostapd_free_hapd_data: Interface wlan0 wasn't started

Note that i tried this while connected to wifi and while disconnected as well (but wifi was up).

If i remove wpa suppliment hook from dhchcd conf file then access point works but not directly. I need to switch between AP mode and client mode.