PROBLEM: The functionality 'Insert your WMS/WMTS URL' in the 'Add a custom base-map' menu does not work and cannot be debugged properly.
BACKGROUND: Following the instructions at CARTODB MAKES IT EASY TO ADD THE PERFECT BASEMAP TO YOUR DATA VISUALIZATION I am attempting to add a WMS as a basemap. The WMS that I am using is dem_hillshades which I have copied from NOAA. Having tested the WMS in my browser (Chrome) and desktop GIS (QGIS) I can confirm that it works without problems in those clients.
ERROR: I am receiving the following error from carto.com 'The URL is either invalid or contains unsupported projections'.
First of all the URL is not invalid since it has been tested in the browser & desktop GIS and also having tried a
GetMap request using the same link and adding the 'SRS=4326' parameter which is what carto.com supports does not address the problem.
Any ideas of similar experiences would be more than welcome.