I am unable to choose the file by mail option for my state tax return. It is there, but I can't click on it.

Yes, it does. If you’ve elected to pay the TurboTax fees through your refund, the File by Mail option won’t be available. Change your payment method, return, and follow the steps.

https://ttlc.intuit.com/replies/3401713

Instructions to print and file by mail:

1. Sign in to your TurboTax Online return.
2. Click File and you’ll get to the [Your name], just (…) more steps and we'll file your returns screen.
3. Complete Steps 1 and 2 if you haven’t already done so, then click Start next to Step 3.
4. On the Let’s get ready to e-file screen, select File by mail, then on the pop-up screen make sure you select File by mail for federal and all of your states.
5. Follow the onscreen instructions to print your return.