Linux Mint 18.3 Synaptic - Opera - Could not resolve host

Using Linux Mint 18.3 on Dell XPS 15 laptop. My update manager is having some issues, I am having difficult time troubleshooting it. It complains that: Failed to fetch https://deb.opera.com/opera-stable/dists/stable/InRelease Could not resolve host: deb.opera.comSome index files failed to download. They have been ignored, or old ones used instead. I can in fact ping deb.opera.com Also, I can navigate to https://deb.opera.com/opera-stable/dists/stable/ using opera, and I do see there is an InRelease file. What is going on? How can I troubleshoot this?