I tried the same and it worked without problems. The authentication for Web Services published in the Denodo Platform happens on two different levels:
First, you authenticate against the web service itself. You can configure this in the Settings tab of the a web service in Denodo. You can take a look at this section of the documentation: [Settings Tab (REST)](https://community.denodo.com/docs/html/browse/7.0/vdp/administration/publication_of_web_services/publishing_rest_web_services/settings_tab_rest). Also, check the [Web Services Authentication](https://community.denodo.com/docs/html/browse/7.0/vdp/administration/publication_of_web_services/web_services_authentication/web_services_authentication#authentication-methods-support-by-soap-and-rest-web-services) for a better understanding of the different authentication methods provided by Denodo.
Second level is how the web service authenticates against the VDP Server. You can configure this when deploying a web service from the VDP Administration Tool. I’d recommend you to check both options again. This section of the VDP Administration Guide explains the different alternatives: [Web Service Container Status Table](https://community.denodo.com/docs/html/browse/7.0/vdp/administration/publication_of_web_services/web_service_container_status_table/web_service_container_status_table) as well as [How Web Services Query the Virtual DataPort Server](https://community.denodo.com/docs/html/browse/7.0/vdp/administration/publication_of_web_services/how_web_%20services_query_the_virtual_dataport_server/how_web_%20services_query_the_virtual_dataport_server).
Further, I’d recommend to check if it works from another browser to discard it is a browser issue or any other client tool.
Hope this helps!