Since you're using TurboTax Online, try closing the program, clearing your Cache and Cookies and re-try your Coinbase account link.
If this doesn't work and you want to move on with your life, save a copy of your Coinbase file to your computer.
Review the transactions and if you have different types of transactions, you may need to enter them in different areas in TurboTax and summarize the totals in each category.
You have your Coinbase file as documentation, if needed.
Click this link for more info on How to Report Crypto Transactions.