wlan1: failed to select channel

hello all,

i have a ptp link between two RB912UAG-5HPnD
from time to time the one used as bridge, stops working with these messages in log file

wlan1: must select channel
wlan1: failed to select channel

this is the configuration:

/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
add authentication-types=wpa-psk,wpa2-psk,wpa-eap,wpa2-eap eap-methods="" \
    group-ciphers=tkip,aes-ccm management-protection=allowed mode=dynamic-keys \
    name=kokoriko supplicant-identity="" unicast-ciphers=tkip,aes-ccm
/interface wireless
set [ find default-name=wlan1 ] ampdu-priorities=0,1,2,3,4,5,6,7 band=5ghz-a/n \
    basic-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,54Mbps \
    channel-width=20/40mhz-Ce country=no_country_set disabled=no frequency=5500 \
    frequency-mode=manual-txpower ht-basic-mcs="mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mc\
    s-5,mcs-6,mcs-7,mcs-8,mcs-9,mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15,mcs-16\
    ,mcs-17,mcs-18,mcs-19,mcs-20,mcs-21,mcs-22,mcs-23" mode=bridge \
    multicast-helper=full noise-floor-threshold=-110 nv2-cell-radius=10 \
    nv2-security=enabled rate-set=configured rx-chains=0,1 security-profile=\
    kokoriko skip-dfs-channels=all ssid=twmn::phil2lewis station-roaming=\
    enabled tdma-period-size=auto tx-chains=0,1 wireless-protocol=nv2-nstreme \
    wmm-support=enabled
/interface wireless nstreme
set wlan1 enable-polling=no framer-policy=best-fit

what am i doing wrong ?
Screenshot 2024-04-04 at 11.07.43 PM.png

Hi,
We’re having the same issue on RBLHG-5nD running ROS 6.49.15 stable.
Does anybody have an idea?
I really appreciate any help you can provide.

/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
add authentication-types=wpa-psk,wpa2-psk,wpa-eap,wpa2-eap eap-methods="" \
    group-ciphers=tkip,aes-ccm management-protection=allowed mode=dynamic-keys \
    name=kokoriko supplicant-identity="" unicast-ciphers=tkip,aes-ccm

Why?

Could there be a DFS event before the error? Have you enabled wireless debug logging?

OP has fixed frequency to 5500. Maybe this channel is occupied in the exposed environment and so the device can’t use/select this channel.