Add the store code [store_code] ValueTrack parameter to your ads redirect [ads_redirect]
On this page
Reasons why the issue is happening
One or more of your products has a missing store code [store_code]. When using the store-specific product page with in-store availability and price feature, you must provide the store code [store_code] ValueTrack parameter to your ads redirect [ads_redirect].
How to fix the issue
Fix products one by one directly in Merchant Center
Go to Products in the Merchant Center, then select the Needs attention tab.
Use the filter icon 
above the table to find all products affected by your issue.
Click on the title of the product you want to fix, then click Edit product.
Filter the downloaded report so that you only view products with:
“Issue title” = Missing [store_code] ValueTrack parameter in ads redirect [ads_redirect]
Update those products data to ensure ads redirect [ads_redirect] has a store code [store_code] ValueTrack parameter.
Select Save.
Fix multiple products at once
Go to Products in the Merchant Center, then select the Needs attention tab.
Use the filter icon above the table to find all products affected by your issue.
Select the Download icon 
to download a list (.csv) of all affected products for all issues or this particular issue.
Filter the downloaded report so that you only view products with:
“Issue title” = Missing [store_code] ValueTrack parameter in ads redirect [ads_redirect]
Update those products data to ensure ads redirect [ads_redirect] has a store code [store_code] ValueTrack parameter.
Reupload your corrected product data to the Merchant Center using your chosen upload method.
Note: It may take some time for your change to be reflected on the Diagnostics page.