The destination site is refusing to load inside the mobile site. Menu item URLs and campaign URLs open in an embedded frame; when the destination's content-security-policy does not allow your platform domain as a frame ancestor, the browser shows a blank page.

Immediate fix

Open the URL in a new tab instead of a frame.

  1. For a menu item: under Platform Admin → Enabled Features → Mobile Store Sites, open the template and the menu item, select Open in New Tab, select Save, then Save Changes.
  2. For a triggered campaign: on the campaign's Creative → Call to Action tab, switch Open Campaign URL in New Tab on and select Save Changes. Turn off any pop-up message first under Interaction Settings. See Create a call to action for on-rotation campaigns.

Longer-term fix

Ask the destination site's webmaster to allow your platform domain in its content security policy, for example:

content-security-policy: frame-ancestors 'self' *.yourdomain.com;

If the platform runs on your organisation's primary domain, your own sites are likely to allow it already.