Could you please share more details about the error message within your flow?
Do you mean that the Getblobcontent Dynamic content in your flow is not passed from your app?
Please check if you have passed proper Blob content path from your app to your flow.
In addition, please check if you have provided a proper value for the Getblobcontent argument of your 'YourFlowName'.Run() function in your app.
Please also consider re-create an new app, and add your flow connection within it, try your 'YourFlowName'.Run() function again, check if the issue is solved.
More details about starting a flow from an app, please check the following article: