Unable to add gateway URL to the Workspace app. Your account cannot be added using this server addre

Account Adding failure in Citrix Workspace via inputing Gateway FQDN with below error: "Unable to add gateway URL to the Workspace app. Your account cannot be added using this server address. Make sure you entered it correctly. You may need to enter your email address instead."...

VA VD 1912 CU1 : Firefox browser unable to detect workspace 1912

Firefox browser does not automatically detect Citrix Workspace...