it is a networking issue
first, unplug your networking after you check it first
go cmd and type it
ping 192.168.1.1
if ping reply then everything is good
if ping show error then its networking issue
make sure check your networking devices first
window defender is secure from malware and spyware virus
but it is not protected from trojan horse virus
I recommend using avg internet security antivirus
it is not heavy as compared to Kaspersky antivirus