Unlocking the Chroma Grimoire Card
If you believe that you are encountering this issue, please wait until the next Weekly Reset. On your first login for the week, head straight to you Postmaster on your first character login. Then, immediately retrieve and open the Sterling Treasure given by your Postmaster.
Do not switch characters, or complete any activities which award Sterling Treasure prior to retrieving and opening your Sterling Treasure from your Postmaster. Furthermore, do not transfer this Sterling Treasure to another character using the Vault or Companion App functions. Please open this Sterling Treasure immediately on the character which it is first received on.
For more information on Chroma, please see: CHROMA FAQ