Is the EIN you are trying to use a 9 digit number in this format: 12-3456789
The hyphen that TurboTax automatically inputs should not matter, but if it is not exactly nine digits, there may be a typo on your W-2G from the casino. If you have ever received another W-2G from them, you can use the federal ID number from another form. You can also try contacting the payer to verify that the Federal ID number reported on the form is correct.. Their phone number should be next to the federal ID number on the form.
To enter the W2G, instead of using the Jump to link, you can also go to the Federal > Wages & Income > Less Common Income > Gambling Winnings.
@kane714
