G3100 router dropping internet connection

My wife called that the Internet was out. When I returned home around 6 pm I reset the router and the problem resolved. I copied some of the log information showing the problem occurred around 9 am this morning. The first dnsmasq err line is repeated continuously up to the router restarting.

There is a repeated warning of a possible DNS-rebind attack detected. 192.168.1.89 is the ip address of our Synology NAS.

2020 Jan 28 09:09:03 dnsmasq err [SYS.3][SYS] failed to send packet: Resource temporarily unavailable
2020 Jan 28 09:06:11 arc_wlsta_monitor info [WIFI.6][SYS] ACTION=de-assoc, WLAN=wl0, MAC=7c:a1:ae:eb:5f:c8, RSSI=0, RATE=0 Mbps
2020 Jan 28 08:54:12 arc_wlsta_monitor info [WIFI.6][SYS] ACTION=de-assoc, WLAN=wl0, MAC=8c:79:f5:ac:1f:72, RSSI=0, RATE=0 Mbps
2020 Jan 28 08:54:01 arc_wlsta_monitor info [WIFI.6][SYS] ACTION=assoc, WLAN=wl0, MAC=8c:79:f5:ac:1f:72, RSSI=-34, RATE=1 Mbps
2020 Jan 28 08:44:28 arc_wlsta_monitor info [WIFI.6][SYS] ACTION=assoc, WLAN=wl0, MAC=7c:a1:ae:eb:5f:c8, RSSI=-80, RATE=130 Mbps
2020 Jan 28 08:33:27 dnsmasq warning [SYS.4][SYS] possible DNS-rebind attack detected: 192-168-1-89.abcdefghijklmnopqrstuvwxyz012345.plex.direct

Anyway, I am interested in whether you can shed any light on what happened. The router (G3100) was sitting with its regular white circle and was supporting wifi connections but no internet connection.