How to solve microdata error for Google Merchant?
You will get microdata missing errors if you have activated Automatic Item Update from Google Merchant but your site template does not have
information to collect product information. To solve the
issue either you have to disable Automatic Item Update from Google Merchant or install and configure this free plugin ( https://wordpress.org/plugins/all-in-one-schemaorg-rich-snippets/ ) into your site and wait few days until google crawls your site and update the information.
Here are the screenshots to disable Automatic Item Update from Google Merchant:
Disable automatic item update from here.