According to the App your Warlock does not appear to have a Power weapon equipped. You either need to equip a power weapon or, if you have an Exotic weapon equipped in that slot, swap it out for a different weapon on the chance that it has been temporarily disabled due to an issue. [i]Edit: After checking in game, it appears as though certain Grenade Launchers in the Power slot have been disabled, likely in response to a bug that increased their damage by %150, rather than the 10% planned in the Seasonal patch.[/i] (΄◉◞౪◟◉｀)