Throw error if hub_url is not present in site_config
diff --git a/erpnext/hub_node/doctype/hub_settings/hub_settings.py b/erpnext/hub_node/doctype/hub_settings/hub_settings.py
index 96e3148..e445531 100644
--- a/erpnext/hub_node/doctype/hub_settings/hub_settings.py
+++ b/erpnext/hub_node/doctype/hub_settings/hub_settings.py
@@ -21,6 +21,8 @@
 			frappe.throw(_("Please select a Price List to publish pricing"))
 
 	def get_hub_url(self):
+		if not frappe.conf.hub_url:
+			frappe.throw('hub_url is not set in site_config')
 		return frappe.conf.hub_url
 
 	def register(self):