Unable to create new WMS item in AGOL

[TrishPeller]

Hello, I am trying to create a new WMS item in ArcGIS online. The url is the following: https://geoserver.sfei.org/prd/sfeiwebservices/wms. When I try to do this, I get an error, saying "Service does not exist or is inaccessible." To the best of my knowledge, there are no custom parameters. 

Any ideas about what I'm doing wrong?

[Laura_B]

Hi @TrishPeller , it looks like that WMS service doesn't resolve on the browser. 

Given that, I also saw the same error on the UI, and a 403 proxy error on the network traffic.