When Withdraw is greyed out, the Earnings screen says why, just under the button. There’s one reason at a time, and fixing it shows the next one if there is another.

What the message means

You seeWhat to do
How much more you need, like $2.40 more to reach the minimumKeep earning. Money On hold doesn’t count until it frees up.
Your request for … is waiting for review.Wait until it’s sent. Tap View request to see it.
To withdraw, add a phone number or turn on two-factor authentication.Tap Add a phone number or Turn on two-factor authentication. Either one is enough.
Add where we should send your money before withdrawing.Tap Add payout details.
Payouts in … haven’t started yet.Nothing to do. You keep earning, and your balance waits until payouts open in your country.
Payouts are paused on your account.Tap Contact support. Your balance is safe while it’s paused.

I turned off two-factor authentication

If two-factor was what kept your account safe, turning it off stops your next withdrawal until you add a phone number or turn it on again. A request that’s already waiting is still sent.