At least post your configuration ... we can't guess which bands or 802.11 protocols you have enabled.
/interface wireless export
This is the configuration:
/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
add authentication-types=wpa2-psk eap-methods="" mode=dynamic-keys name=profile1 supplicant-identity="" wpa2-pre-shared-key=xxxxxxxxxxxxx
/interface wireless
set [ find default-name=wlan1 ] adaptive-noise-immunity=ap-and-client-mode antenna-gain=4 band=2ghz-b/g/n basic-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,54Mbps basic-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps bridge-mode=disabled country=\
italy disabled=no distance=indoors frequency=2437 frequency-mode=regulatory-domain ht-basic-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7,mcs-8,mcs-9,mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15 ht-supported-mcs=\
mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7,mcs-8,mcs-9,mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15 installation=indoor keepalive-frames=disabled max-station-count=100 mode=ap-bridge multicast-buffering=disabled multicast-helper=disabled \
rate-set=configured security-profile=profile1 ssid=WIFI-TEST wps-mode=disabled
/interface wireless nstreme
set wlan1 enable-polling=no
/interface wireless snooper
set receive-errors=yes