Let me step in and assist you on how to upload your receipts quickly.
First, you can check your data connection on your device. If it's connected to Wifi, turn it off and use cellular data. If it's connected to cellular data, try to connect to your Wifi.
Next is to clear the data from your app. This way, it will delete some of the data to free up the storage of your QuickBooks Self-Employed app. Here's how:
For Andriod:
Go to your mobile device settings.
Select the Apps tab.
Look for the QuickBooks app.
Click the Storage button.
Hit Clear data.
For iOS:
From your device's Settings, look for Setting General iPhone Storage.
Choose an app that's taking up a lot of space.
Select Offload App to free the storage without deleting the documents and data from your app.
Once done, restart your device to refresh the app.