...
Connecting to WMS/WFS Server
Add www.daveyresourcekeeperhttp://geocomyt.daveytreekeeper.com/ (please contact the TreeKeeper Support Team for the exact domain name) to your organization settings "Trusted Servers" within ArcGIS Online.
...
We can find "Trusted Servers" on the linked page above.
Enter "httpshttp://wwwgeocomyt.daveyresourcekeeperdaveytreekeeper.com/" in this settings field, and click Save at the bottom of the page.
...
For WMS Layers, please select "A WMS OGC Web Service" and enter the following URL: https://www.daveyresourcekeeper.com/geoserver/TreeKeeperWMS/wmsURL given to you by support staff.
For WFS Layers, please select "A WFS OGC Web Service" and enter the following URL: https://www.daveyresourcekeeper.com/geoserver/TreeKeeperWFS/wfsURL given to you by support staff.
...
Then, click "GET LAYERS", and the login window should pop up in your browser. Please enter your credentials, and the following should show in the Layers menu:
...