It was identified today that sites using the Simply White theme will not display AdSense ad blocks in either the sidebar or content areas. Changing to any other theme will enable your ad blocks to display, as all other themes have been verified to properly display ad blocks.
Please note that changing your theme will remove any customization via the Colors and Fonts tab in your site's control panel. You will need to manually reapply these changes after changing your theme.
Google has been notified of the issue.
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