> For the complete documentation index, see [llms.txt](https://galmis.gitbook.io/barcodify-customer-selector/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://galmis.gitbook.io/barcodify-customer-selector/troubleshooting/known-issues-and-workarounds/expected-a-valid-shop-query-parameter.md).

# Expected a valid shop query parameter

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This issue should no longer occur. However, if you know how to recreate it, I'd appreciate it if you could share your insights.
{% endhint %}

Sometimes, you may notice a black screen with the "**Expected a valid shop query parameter**" error. Generally, this occurs when the app authenticates the user.

To work around it, please open the app with the shop parameter populated in the address bar, i.e. add **?shop=mystorename.myshopify.com**. For example, if your store's myshopify domain was **galmis-test.myshopify.com**, please open <https://galmis-test.myshopify.com/admin/apps/select-customer-with-barcode-1/auth?shop=galmis-test.myshopify.com>.

<figure><img src="/files/uXeVVCJI9jZgvkEKr3zy" alt=""><figcaption></figcaption></figure>

After successfully loading the app, the error should no longer occur.