Many games, those with a Cash Respins or Emerald Link, include a Grand Jackpot which you can win when you fill all the slot spaces with the correct symbols during the feature.
A minimum bet is required to be eligible to win it though.
If your Grand Jackpot indicator is greyed out, then you need to increase your bet to activate the feature.
If you have met the Jackpot minimum bet requirement and your Grand Jackpot was not activated, try and grab a screenshot of this issue and contact our Support team with as much information as possible and they'll be happy to assist.