In TMAC , the iframe could not be loaded due to cross domain. TMAC Proxy is using different domain from TMAC UI.The error can be found as below from developer tools(F12)
Campaign Selector UI is hosted from different domain, in this case specify the full url in globalvars.js
From the IIS, for TMAC UI, select the below module HTTP Response Headers
Enter the X-Frame-Options as value="ALLOW-FROM *"
Alternatively, we can the below in Web.config when no IIS access.
<add name="X-Frame-Options" value="ALLOW-FROM *" />
Issue will be resolved loading the iframe as below.