I am trying to add a layer from a URL to my AGOL webmap. The website containing the data is https://data.apps.fao.org/wapor/?lang=en. In the left pane if you click "About This Data" that will open a pop-up with more information. At the bottom of this pop-up is a WTMS URL (link copied below). I tried using this link directly to add a layer to my map but got an error "Service does not exist or is inaccessible." I then replaced tilematrixset={srs} with tilematrixset=EPSG:4326 but still have the same error.
Web Map Tile Service (WMTS) URL
https://data.apps.fao.org/map/wmts/wmts?layer=fao-gismgr/WAPOR-3/mapsets/L1-AETI-A&tilematrixset={srs}&Service=WMTS&request=GetTile&Version=1.0.0&Format=image/png&TileMatrix={z}&TileCol={y}&TileRow={x}&layertype=Image
Next, I tried to instead add it as a Tile Layer. ESRI expects a format of:
https://{subDomain}.domain.com/<path>/{level}/{col}/{row}.png
where subDomain is optional. I rewrote the URL as follows:
https://data.apps.fao.org/map/wmts/wmts?layer=fao-gismgr/WAPOR-3/mapsets/L1-AETI-A&tilematrixset=EPSG:4326&Service=WMTS&request=GetTile&Version=1.0.0&Format=image/png&TileMatrix={level}&TileCol={col}&TileRow={row}&layertype=Image.png
I tested this url in a browser by entering {level} as 2, {col} as 2, and {row} as 1 and I see the associated tile image.
https://data.apps.fao.org/map/wmts/wmts?layer=fao-gismgr/WAPOR-3/mapsets/L1-AETI-A&tilematrixset=EPSG:4326&Service=WMTS&request=GetTile&Version=1.0.0&Format=image/png&TileMatrix=2&TileCol=2&TileRow=1&layertype=Image.png
Using the link above, I tried to add a layer from URL as a Tile Layer. A layer was created but it is empty and I don't know how to troubleshoot the issue further.
Can someone help me figure out how to properly add this data from URL?