adblock – How to disable adblocking in safari?

I am using Safari version 12.1 (13607.1.40.1.5).

If I go to Safari-> Preferences-> Extensions shows that I do not have any extensions installed.

When I visit http://kmlviewer.nsspot.net, I press the button "choose a file" and I select a kml file. I receive the message:

"Please disable the adblock for free use."

If I go to Safari-> Settings for this website, "Enable Content Blockers" is unchecked, "AutoPlay" is set to "Allow AutoPlay", and "Pop-up Windows" is set to "Allow"

I do not see any other settings that could further disable ad blocking. Is there anything else I can do?

There are several examples of kml files, but you can use the text of:

https://gist.github.com/EricG-Personal/589b293297f42759ba32dea3df04a7b5

and easily create your own .kml file.