Can’t ping other devices connected to hotspot

[xrisk]

When I have more than one device connected to the hotspot, they are invisible to each other. Any packets I send to them don’t reach and I can’t ping them. Each device can ping the router fine, and the router can ping both devices.

OS: Pop!_OS 21.10

Network controller: Broadcom Inc. and subsidiaries BCM43602 802.11ac Wireless LAN SoC (rev 01) Subsystem: Apple Inc. BCM43602 802.11ac Wireless LAN SoC Kernel driver in use: brcmfmac Kernel modules: brcmfmac

create_ap.conf

CHANNEL=default
GATEWAY=192.168.12.1
WPA_VERSION=2
ETC_HOSTS=0
DHCP_DNS=gateway
NO_DNS=0
NO_DNSMASQ=0
HIDDEN=0
MAC_FILTER=0
MAC_FILTER_ACCEPT=/etc/hostapd/hostapd.accept
ISOLATE_CLIENTS=0
SHARE_METHOD=nat
IEEE80211N=0
IEEE80211AC=1
HT_CAPAB=[HT40+]
VHT_CAPAB=
DRIVER=nl80211
NO_VIRT=0
COUNTRY=
FREQ_BAND=5
NEW_MACADDR=
DAEMONIZE=0
DAEMON_PIDFILE=
DAEMON_LOGFILE=/dev/null
NO_HAVEGED=0
WIFI_IFACE=wlp3s0
INTERNET_IFACE=enx00e04c103d56
SSID=xxxx
PASSPHRASE=xxxx
USE_PSK=0