Cash Out Suspended on DraftKings means that you are unable to cash out your bet early at that moment.
On DraftKings Sportsbook, you typically have the option to Cash Out any bet that you have already placed. The amount that you can cash out will fluctuate based on the results of a game as they happen.

Using Cash Out can be another way to hedge your bet, so having Cash Out suspended can be frustrating for those looking to get out of a bet.
Why Does DraftKings Suspend Cash Out Bets?
DraftKings Sportsbook has a lot of surface area to cover. There are games happening all the time, and DraftKings typically offers all sorts of live odds and props.

To cover their bases, DraftKings will sometimes suspend the Cash Out option. This is to limit their risk and exposure, especially while a game is in play. DK is in the business of making money, after all!
For example, if you bet on the Chicago Cubs moneyline and there was an umpire review on a potential game winning home run. DraftKings might choose to suspend the Cash Out Bet option to avoid someone cashing out when the call on the field may be overturned.
DraftKings may also suspend Cash Out bets at later stages of a game. Many live betting models have a hard time handling some of the behavior of late game scenarios, so DK likely wants to limit their exposure to any quirks to their pricing.
Why is Cash Out Greyed Out?
Cash Out is greyed out because DraftKings is suspending the option for you to cash out. When the option is available again, there will be a button that says “Cash Out for $X”.
It is possible (and likely) that the option will return, so keep an eye on your Open bets to see if/when the option becomes available.