@Jackob_K Thanks for reaching here! Could you confirm you are using subscription and same resource group as your AI Foundry hub. Also-select a location in which to deploy the web app. You can use the same location as the hub.
Later you configure authentication for the web app in the Azure portal.
Reference- https://learn.microsoft.com/en-us/azure/ai-studio/tutorials/deploy-chat-web-app#deploy-your-web-app