utag_data should be defined and populated prior to loading the Universal Tag.
<!-- Tealium Universal Data Object -->
"page_name":"Men's Fashion | Acme Inc.",
The path to the utag.js file comprises the following attributes:
Account - the name of your account in Tealium iQ
Profile - the name of the profile within your account (“main” is the default)
Environment - one of three default publish environments: dev, qa, or prod
The Tealium code is designed to be placed after the opening <body> tag (as opposed to the <head> tag). This positioning provides the best compatibility with the greatest number of vendors and allows third-party tracking to complete before the visitor navigates to the next page. The utag.js code can be placed anywhere within the <body>, although the top is the preferred location. The sooner the page can begin loading utag.js the sooner your tags will be ready to run when the page has been rendered.