google base google shopping help

I need bit of help please as not 100% sure what I'm doing. I've got a ecommerce website that is using opencart 3.0.3.8 and I'm trying to get the products into Google shopping.

I'm using the built in google base feed

I'm using Google merchant center next and I have managed to get 57 products approved but it says 271 are not approved and they are saying "Invalid GTIN
Add an accurate GTIN and make sure it only contains numerals" but I checked the file http://shop.it-doneright.co.uk/googlebase.xml and it's got the gtin number and is 12 digits so looks to be the correct amount of numbers.

It also says about "XML formatting error. Your feed contains a character that is not permitted in UTF-8 encoding."

I'm bit lost on how to fix the issue as don't do this often but I thought if it worked for 57 products, it should work with the other remaining products.

I also noticed that not all products are submitted to google, the products are in the googlebase.xml file but not submitting to Google merchant center next unless it's due to the errors.

Can anyone help and offer advice please or have a look

Did you look into data for which items were approved? Why they got approved or submitted may be compare it with one which is not being submitted or approved.

Sync to GMC can be painful but its always do able.

khnaz35 wrote: ↑

Mon Jul 21, 2025 2:27 am

Did you look into data for which items were approved? Why they got approved or submitted may be compare it with one which is not being submitted or approved.

Sync to GMC can be painful but its always do able.

How do I find out why some items got approved and others didn't? Where do I find the data that shows the items that got approved?

khnaz35 wrote: ↑

Mon Jul 21, 2025 2:27 am

Did you look into data for which items were approved? Why they got approved or submitted may be compare it with one which is not being submitted or approved.

Sync to GMC can be painful but its always do able.

I've managed to click on edit product on a approved product and a non approved product and the fields are filled in for both but the non approved product is saying "Invalid GTIN. Add an accurate GTIN and make sure it only contains numerals". The number in the field is "471138783783" which looks to be correct so don't understand why it's saying that. The number for the approved product is "730143314466"

GTINs have a check digit, so you don't just need to have the correct number if digits. Use an online GTIN check to check it's valid.