I'm sorry to hear that you encountered an issue when accessing the "Pages and screens: Page title and screen class" report in Google Analytics and filtering the first column by "content group". Based on my research, it seems that Content Grouping is not retroactive. The Content Groups that you create are valid only from the creation date forward. You create Content Groupings at the view level, under Admin > > Content Grouping. You can check to see if the content group is firing by using an extension such as Google Analytics Debugger (Chrome) or HTTPFox (Firefox), and look for the content group parameter in the request. If people can’t access your group, or your group doesn’t appear in search results, check your group visibility settings. This setting controls the visibility of the group, regardless of the visibility of individual conversations, or who can or cannot join the group. I hope this helps. Let me know if you have any other questions.

It looks like you are trying to set up content groups in your GA4 Google Analytics account in order to group your website pages. You followed the instructions in this article: https://support.google.com/analytics/answer/11523339?hl=en, where you added the following code after your GA4 script:

where ZZZ is a different value on each webpage. However, when you filtered the "Pages and screens: Page title and screen class" report by "content group", you only saw a blank line and not the ZZZ values. Based on the information you provided, it's difficult to determine what the issue might be. However, here are some possible reasons and solutions: - Double check that you have added the code to each webpage correctly. Make sure that the value for ZZZ is different on each page and relevant to the group of pages you want to track. - Wait for some time. It can take up to 48 hours for the changes to reflect in your Google Analytics account. This might be the reason why you are not seeing the values yet. - Check if you have permission to view content group data in Google Analytics. You need to have "Read & Analyze" permission to view content group data. - Verify that you are using the correct property ID. Double check the property ID in the gtag() code by going to the Google Analytics property and checking the Tracking ID value. - Ensure that you have actually grouped your pages together. If the value for ZZZ is not properly set, or if the pages are not actually grouped, nothing will appear in the "content group" filter in the "Pages and screens: Page title and screen class" report. I hope this helps! If you're still having issues, it might be worthwhile to reach out to the Google Analytics Support Team for further assistance.