Link my RBS account to my Quickbooks. It’s taking me to the RBS page and asking me to select the account. Once I’ve selected the account, instead of taking me back to Quickbooks it’s coming up with a message on the screen saying authorisation input failed

I can help you link your bank account to QuickBooks Self-Employed (QBSE), @userelitetvandfilmse.

To resolve the error you're having when trying to connect to Royal Bank of Scotland (RBS bank), I suggest going to your online banking account and verify if you need to accept new terms of service, acknowledge any announcements about maintenance or other site changes or new offers.

Once done, go back to your Bank accounts page in QBSE to connect your bank account again. 

Check these articles for more information: 

• Connect bank and credit card accounts to QuickBooks Self-Employed
• Fix bank error 108

Here's a guide to help you add older transactions to QuickBooks Self-Employed. 

I'm always here if you need more help connecting your bank account here in QBSE. Take care and have a great rest of the day!