Problem Adding WMS Service

I'm trying to add a OGC WMS map service to my site.

for example: http://wms.alaskamapped.org/ortho? or http://webservices.nationalatlas.gov/wms/water?

both work in ArcMap, but when I try to add them to my site as an OGC WMS, I get the following error:

The URL 'http://webservices.nationalatlas.gov/wms/water?' does not appear to reference a valid WMS map service. Underlying error: WMS: An unknown error occurred while initializing the map service.

I'm using 3.11.0, but I was also having the same results with 3.10