Apr 15, 2019

Debug / Preview Mode not working in Chrome and Safari

Hi there,

I have succesfully implement Google Tag Manager on our website (tested with Tag Assistant). But i can not access the preview / debug mode on Chrome or Safari. If I click on preview mode, the page starts loading, and after a few seconds the same workspace (without the preview mode) will appear.

Does anyone has this problem as well?
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All Replies (12)
Apr 16, 2019
Hi

Make sure you are not blocking third-party cookies in the browser settings (Safari does so by default), and make sure you don't have a plugin or extension (such as Ghostery) that might block third-party cookies and/or Google Tag Manager.

Simo
May 26, 2019
Thank you so much. It helps me))))) It is working now, finally!!
Google user
Jun 4, 2019
Tag Manager was working fine, all tags firing off, then suddenly with no changes it stops working and the debug won't display.  

Note:  I have not switched browsers, adjusted settings or anything.  I literally logged on today and I can't preview my site.
Oct 23, 2019
I'm using a Wix site and preview mode will not load. Any Wix users out there?
Oct 24, 2019
to User 670748464457551327
What have you tried so far to debug this situation? Have you tried these methods? https://www.analyticsmania.com/post/google-tag-manager-preview-mode-not-working/

Wix is not special in any way, just another website builder. So the tips from the link above should be enough to find a problem. If not, let us know and we'll see what we can do.
Nov 18, 2019
Hi,

I am also having this issue. Right in the middle of showing someone how to use preview mode it stopped working - that is I press the "preview" button, the screen refreshes, but there is no preview panel. I had thought it was something to do with logging into a DoubleClick account at the same time (jury is still out on that one), but I have:-
  • logged out of other accounts (as much as I think I can?)
  • cleared cookies
  • cleared localstorage
  • switched off all extensions
  • closed all instances of chrome in the task manager
  • restarted the computer
  • made sure 3rd party cookies are allowed
  • Running latest Chrome (78.0.3904.97 at time of writing)

It works on edge and I have a Chrome version that runs in a "low security" mode that uses a flag --disable-web-security that also works. I have a laptop running the same version of Chrome with the same user account and it works too, so I can't think what would have changed on my PC. Any help would be appreciated.

Thanks,
Jarrod
Nov 21, 2019
Same issue here. After pressing preview button, debugger window is not showing, permission for 3rd party cookies is on, cleared cache, history, closed and refreshed windows, disable cache with DevTools opened, working with Chrome. I have tried several times and no luck. Any suggestions?

Nov 26, 2019
Thanks, it's worked . my chrome Block third-party cookies
Google user
Dec 5, 2019
I am also having issues with this. The issue appears to specifically be that preview mode isn't starting in Tag Manager in the first place, i.e. no orange preview bar appears in Tag Manager after clicking "preview". The page shows a "Saving..." toast then refreshes and the workspace appears as normal, not in preview mode.

3rd-party cookies are disabled, as are any other extensions that would block 3rd-party content such as Adblock Plus, Ghostery, and DuckDuckGo.
Last edited Dec 5, 2019
Dec 10, 2019
"Third party cookies are disabled" - there's your problem.

Or was that a typo?

Try with another browser that doesn't block 3P cookies, e.g. Firefox in Standard protection mode.

Simo
Google user
Dec 13, 2019
Almost the same issue here. It works fine on FireFox and InternetExplorer and when I log in to my chrome profile by the laptop or another pc it works perfectly too. Are there any further suggestions out there I/we could try? Thanks!
Dec 16, 2019
[SOLVED] - Reinstall of Chrome Browser solved my issue. *interesting*

I now experience the same issue. I've tried clearing cache, cookies, reset any flags to default, adding allow exceptions to [*.]tagmanager.com etc. 

No extensions active.

I'm on iOS Chrome latest stable version. 
Now tested with Version 79.0.3945.79 (Official Build) beta (64-bit) -  Same result.

Did a test on Safari browser and a message box popped up when clicking Preview the first time. Preview didn't load either. 

Console Warning: "A cookie associated with a cross-site resource at https://www.googletagmanager.com/ was set without the `SameSite` attribute. It has been blocked, as Chrome now only delivers cookies with cross-site requests if they are set with `SameSite=None` and `Secure`. You can review cookies in developer tools under Application>Storage>Cookies and see more details at https://www.chromestatus.com/feature/5088147346030592 and https://www.chromestatus.com/feature/563352162218803"

No Console Errors.

For now I've resorted to using the chrome extension: https://dataslayer.org/ (if anyone haven't tried it yet) until this works again.
Last edited Dec 16, 2019
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