The recovery server could not be contacted

After I force restarted my computer after failing to load recovery with wifi, I was back at the main install window. I went up the menu located at the top of the screen above and in utilities menu, I opened the program “Network Manager.” The program could not ping google.com, which meant the computer did not have access to the internet. Activating WiFi did not seem possible with this Network program. So I decided to get an Ethernet wire and hook it up to iMac. After restarting “Network” program, the utility can now ping google.com, thus the computer was finally on the internet. And finally I was able to install the MacOS without the pop up message. The only solution that truly works is to use a old fashion Ethernet cable.