Hello, LindaMJ.
It looks like this is your first time connecting your bank with QuickBooks Online. I have a solution to help you fix the 103 error code.
I can see that NatWest has multiple links in our list of banks. This error happens when the bank credentials are used on an incorrect link. You would want to select the correct one (the link you always go to).
You can drop me a comment if there's anything else you need help with.
