Is the app updated? Are you linked if you are you do not need to scan. uninstall reinstall shut phone off on wifi on off clear cookies cache these are the normal fixes. If that doesn't work it could be on ibottas end give it a few hours to a day if that doesn't work you can be locked.
You can just enter the number above the receipt, starts with TC# - select receipt won’t scan and then follow the prompts to enter the scan number- works for me on Walmart receipts