"Treasure hunt" Online issue (Grand Theft Auto 5)

I apologize if this was already post, but I have not found.
Took the quest "treasure hunt" (the Golden revolver) with the email found on the picture hint first. Then as expected, the plot gave 3 where to look for clues. But knocked out session after I entered the game, the quest isn't active, no prompts in the field, the letter does not come new. And quest not fails because of this. Can someone met such a problem. Tell me what to do and how to be? Thanks in advance.