Q: I have deleted the message that contained the riddle and I now can't progress the quest.
A: Deleting the inbox messages will not interfere with the quest progression. If you have accidentally deleted the riddle from your inbox message, Warframe Support cannot restore the deleted message, however the content of the message can be read on this Help Center article here:
Q: I crafted the Mirage Chassis but quest is stuck on last part of the quest.
A: This issue occurs due to how sensitive Warframe's quest system is and how certain quest tasks doesn't track properly when the quest isn't set as your Active Quest at the Codex.
If this happens to you, please "Submit a request” to Warframe Support under "Quests" > Category "Hidden Messages" in order for us to help you progress the quest.
Q: I completed the Hidden Messages quest, but I did not receive the Mirage Blueprint.
A: The main blueprint for Mirage is not part of the quest's reward.
Completing the quest will award you with the Mirage component blueprints (Mirage Neuroptic, Systems, and Chassis). You can craft the Mirage after completing the quest by purchasing the Mirage Blueprint from the market.