Unexpected Blend Error in Looker Studio – No Changes Made

[Villy]

Hi there,

We’re blending Shopify and GA4 data in Looker Studio. It was working fine about 8 hours ago, but when we refreshed the page around 3 hours ago, we started getting this error:

“Invalid combination of metrics and dimensions
Report configuration issue – please select a valid combination of dimensions and/or metrics in the property panel.”
Error ID: 9f9989e3

What’s confusing is that we haven’t made any changes.

At the moment, the blended data only uses GA4 fields: item name, date, and sessions — nothing from Shopify. So the setup should still be valid. We also tried changing the join key — first using just item name, then just date — but the same error keeps appearing.

We double-checked the Shopify data in Google Sheets: no edits, no updates, and no changes in the version history. GA4 looks mostly unchanged too, except for one thing — purchaserConversionRate now shows as purchaser rate. That’s the only difference we’ve noticed, though we’re not sure if it’s related.

For reference, our join keys are:
• GA4: item name + date
• Shopify: product title + day

Both datasets use the same date format: DD/MM/YYYY.

Could this be a temporary Looker Studio issue, or is there something subtle we might be missing?

We’d really appreciate any insight or suggestions. Thanks so much for your time.

[阿泰]

I think your data blending settings might be incorrect. Could you share a screenshot of your data blending setup so we can better understand and clarify your question?

[Villy]

Hi @阿泰, thank you for the response

Here's the data that we have - the left data is from GA4 and the right is from Shopify. We've reduced the data in Shopify before just to check if any dimension or metric is causing the issue

Please let me know what you think

Thank you!

[阿泰]

Most data blending problems usually come from "key matching" issues. I think your "Date" and "Day" fields might not be in the same format, which is why the data can't be combined.

Here’s one way to check if the data is correct:

• Pull the two data sources into two separate tables—one for GA4 and one for Shopify. This will help you verify whether the date fields match correctly.

• Use the auto data blending option to see if Looker Studio can automatically combine the data for you.
• 

[Villy]

Hi @阿泰 , thanks for the response!

We’ve now formatted both dates using a calculated field to make sure they match.

It looks like the issue is with the ‘Item Name’ in the GA4 report. When we remove that dimension, the report works fine. But when we add it back, we get an error. What’s strange is that we’re using ‘Item Name’ in another chart with the same GA4 fields and it works there.

Could this be an issue with how GA4 works with Shopify? It’s a really odd error.

[阿泰]

How about Item ID? It might be a bug. If you’re sure that the GA4 item names all match the Shopify item names.