For security reasons, CRA's NETFILE service will lock your account if you attempt to file and fail 5 times.
You need to call the CRA and ask them to unlock your account.
Then, when you sign back into TurboTax and try to submit to NETFILE again, make note of the error you get.
You'll need to resolve that error before trying to file again or you'll end up with a locked account again.
If you are locked out and CRA says that you are not locked out from their end, please give it time and it should unlock.
Please contact our phone support team or contact us directly on Facebook or Twitter for further assistance.