How to pass IP address to netcat as variable in bash scripting?

I have this script on a Linux machine that loops through a .txt file to see if connection is successful or not. When I give the IP directly is works. However, when I pass the variable it says: nc: getaddrinfo: nodename nor servname provided, or not known. Here is the my script:

#!/bin/bash  

cat ip2.txt | while read line || [[ -n $line ]];
do
    echo $line
    if nc -zv $line 8080 ; then
        echo "Success"
        echo $line >> res.txt
    else
        echo "Fail"
       
   
    fi
done