issue on installing dev apps into the store

[simpledevstore_]

Hi Team,

One of our users, facing an issue while doing install the OAUTH dev app onto the Shopify Store and they didn't allow to install that app. I have tried with my cred and it is working (screenshot attached).

But the user doing the same on their end with their cred and this window shows not linked between the store and apps.

So, could you please let me know why the user app is not installed in the store? need any permission to be enabled?