Could not bind TCP port 80 because it is already in use by another process on this system (such as a web server). Please stop the program in question and then try again. (R)etry/(C)ancel: 

sudo netstat -tulpn | grep 80

tcp        0      0 127.0.0.1:8080                0.0.0.0:*                        LISTEN        3026587/python3

udp6       0      0 :::80                         :::*                        LISTEN        2221248/httpd

udp6       0      0 :::8008                       :::*                        LISTEN        1837883/pegas