Failed to discover a Canon ImageCLASS MF4420n scanner

[Thanos808]

Failed when try to discover a Canon ImageCLASS MF4420n scanner with error message: "skipping, none of supported protocols discovered".

sane-airscan version: 0.99.29-1

airscan-discover -d
MDNS: AVAHI_CLIENT_S_RUNNING
WSDD: netif addresses update:
WSDD: + 193.168.20.113@enp7s0, ifindex=2
WSDD: + fe80::a1fa:e5fb:de44:2652@enp7s0, ifindex=2
WSDD: 193.168.20.113: started discovery, UDP port=44939
WSDD: fe80::a1fa:e5fb:de44:2652: started discovery, UDP port=40995
zeroconf: zeroconf_device_list_get: requested
zeroconf: device_list wait: requested
zeroconf: device_list wait: DNS-SD not finished...
MDNS: browse-ipv6@("_ipp._tcp"): AVAHI_BROWSER_CACHE_EXHAUSTED
MDNS: browse-ipv6@("_ipps._tcp"): AVAHI_BROWSER_CACHE_EXHAUSTED
MDNS: browse-ipv6@("_uscan._tcp"): AVAHI_BROWSER_CACHE_EXHAUSTED
MDNS: browse-ipv6@("_uscans._tcp"): AVAHI_BROWSER_CACHE_EXHAUSTED
MDNS: browse-ipv6@("_scanner._tcp"): AVAHI_BROWSER_CACHE_EXHAUSTED
MDNS: browse-ipv6@("_ipp._tcp"): AVAHI_BROWSER_ALL_FOR_NOW
MDNS: browse-ipv6@("_ipps._tcp"): AVAHI_BROWSER_ALL_FOR_NOW
MDNS: browse-ipv6@("_uscan._tcp"): AVAHI_BROWSER_ALL_FOR_NOW
zeroconf: ZEROCONF_USCAN_TCP: initial scan finished
MDNS: browse-ipv6@("_uscans._tcp"): AVAHI_BROWSER_ALL_FOR_NOW
zeroconf: ZEROCONF_USCANS_TCP: initial scan finished
zeroconf: device_list wait: DNS-SD not finished...
MDNS: browse-ipv6@("_scanner._tcp"): AVAHI_BROWSER_ALL_FOR_NOW
zeroconf: ZEROCONF_MDNS_HINT: initial scan finished
zeroconf: device_list wait: WSDD not finished...
zeroconf: found urn:uuid:01c80000-fe7f-11de-8a39-001e8faed071
zeroconf: method: ZEROCONF_WSD
zeroconf: interface: 2 (enp7s0)
zeroconf: name: -
zeroconf: model: -
zeroconf: addresses:
zeroconf: protocol: WSD
zeroconf: endpoints:
zeroconf: device: 0000 (created)
zeroconf: device_list wait: WSDD not finished...
WSDD: fe80::a1fa:e5fb:de44:2652: done discovery
WSDD: 193.168.20.113: done discovery
zeroconf: ZEROCONF_WSD: initial scan finished
zeroconf: device_list wait: OK
zeroconf: zeroconf_device_list_get: building list of devices
zeroconf: urn:uuid:01c80000-fe7f-11de-8a39-001e8faed071 (0): can: none, use: none
zeroconf: urn:uuid:01c80000-fe7f-11de-8a39-001e8faed071 (0): skipping, none of supported protocols discovered
zeroconf: zeroconf_device_list_get: resulting list:
[devices]
zeroconf: device gone urn:uuid:01c80000-fe7f-11de-8a39-001e8faed071
zeroconf: method: ZEROCONF_WSD
zeroconf: interface: 2 (enp7s0)

On the printer(with scanner ability), the "WSD Print Setting" has been setup as following lines:
Use WSD Printing: On
Use WSD Browsing: On
Use Multicast Discovery: On

On the machine running airscan, I captured the UDP protocol packets during discovery, and find out that the scanner does return contents with xml stuff, but the machine running airscan only returns a ICMP message with Destination unreachable(Port unreachable).