I am asking these questions because I am getting warnings similar to the OP yet my IE was already set to use TLS 1.2, and *arcgis.com was already in my trusted site, and also because it seems like any web connections used should be set in the software's properties independent of any browser.
I got the warning when I changed to OSM basemap - I am going to guess that it is the origin of this 3rd party service that is the crux of the immediate issue, but I don't see any documentation that will let me "trust" it.