If you installed iAdvize through Google Tag Manager (see Install iAdvize via Google Tag Manager), a Safari privacy setting can stop GTM from loading for some of your visitors. When that happens, iAdvize doesn’t load either. This article explains when the setting applies, what it blocks, and how to make your setup compatible.

Safari’s advanced tracking protection

Since Safari 17 (iOS 17 and macOS Sonoma), Apple offers a setting called “Use advanced tracking and fingerprinting protection”. It blocks connections to data collection companies identified as trackers and removes known tracking parameters from URLs.

It applies in two cases:

• In Private Browsing, it’s on by default. Any visitor who opens your site in a private Safari tab is affected, without changing any setting.
• In regular browsing, it applies if the visitor turned it on. On iPhone and iPad: Settings > Apps > Safari > Advanced > Advanced Tracking and Fingerprinting Protection, set to “All Browsing”. On Mac: Safari > Settings > Advanced.

Visitors can turn the protection off for one site by reloading the page with reduced privacy protections. Few do, especially when they don’t know something is missing from the page.

What Safari blocks

When the protection is on, Safari runs a content blocker that stops the browser from contacting known tracker domains. The list is built from the DuckDuckGo and EasyPrivacy lists: a domain is blocked when it appears on both.

The Google Tag Manager domain is one of them. In our tests, Safari blocks the file https://www.googletagmanager.com/gtm.js and logs this message in the console:

Blocked connection to known tracker

Impact on iAdvize

If gtm.js doesn’t load, none of the tags in your GTM container run. For iAdvize, that covers all three tags: the main tag, the transaction tag and the custom data tag. The visitor sees no widget, no engagement notifications and no AI Shopping Assistant.

The impact is wider if your consent management platform (CMP) is also loaded through GTM. The cookie banner doesn’t show, no consent is collected, and an iAdvize tag fired on a consent event never fires. The other tags in the container (analytics, advertising) are blocked the same way, so these visitors are also missing from your analytics tools.

The iAdvize scripts themselves aren’t affected: our tests show that iAdvize loads and displays normally when it isn’t loaded through GTM. Only GTM is blocked.

Check whether your site is affected

1. On Mac, open Safari > Settings > Advanced and tick “Use advanced tracking and fingerprinting protection” for all browsing. On iPhone, open your site in a Private Browsing tab.
2. Open your site and show the Web Inspector console.
3. If you see “Blocked connection to known tracker” on googletagmanager.com/gtm.js and iAdvize doesn’t display, your setup is affected.

The fix: load GTM from your own domain

Safari blocks a domain, not a script. If gtm.js is served from your own domain (for example www.yoursite.com/metrics or metrics.yoursite.com) instead of googletagmanager.com, it’s no longer recognized as a known tracker and loads normally. The tags in your container, including the iAdvize tags, run again.

Google supports this setup through server-side tagging. Your technical team or agency sets it up by following Google’s official documentation:

• Google tag gateway for advertisers: load Google scripts, including gtm.js, from your own infrastructure (tagging server or CDN) instead of Google’s servers.
• Custom domain configuration: serve your tagging server from your domain, on a subdomain or a path of your site.
• Server-side tagging and Client-side tagging vs. server-side tagging: how it works and what each container does.

What changes for iAdvize

Nothing in your iAdvize setup. The iAdvize tags stay in your web container, with the same triggers and variables as in the installation article.

Don’t move the iAdvize tags to the server container. That container doesn’t run in the visitor’s browser, so it can’t display the iAdvize widget. Here, server-side is only used to serve gtm.js from your domain.

After the setup

Run the test above again, with the Safari protection on:

• gtm.js loads from your domain, not from googletagmanager.com;
• your cookie banner shows, if your CMP is loaded through GTM;
• iAdvize displays after consent.

If your CMP loads its own scripts from its vendor’s domain, check that Safari doesn’t block them too.

Sources

• Apple, Browse privately in Safari on Mac: on by default in Private Browsing, can be turned on for all browsing, reload with reduced privacy protections.
• WebKit (Apple’s Safari team), Private Browsing 2.0: blocking of known trackers since Safari 17, DuckDuckGo and EasyPrivacy lists, iOS setting, console message.
• Tracker lists used by Safari: DuckDuckGo Tracker Blocklists and EasyPrivacy.
• Google, Google tag gateway for advertisers, Custom domain configuration, Server-side tagging, Client-side tagging vs. server-side tagging.