I joined the Thieves Guild and started the main questline however I can't seem to move forward with it. I completed the quest "Loud and Clear" and now Brynjolf won't give me the next quest. Every time I talk to him he simply says, "Sorry lad, I've got important business to take care of. We'll talk later." I have done numerous side jobs for Vex and Delvin and even the special jobs in Markarth, Windhelm, Solitude, and Whiterun. I would like to complete the main questline though. Please help, I don't have a clue how to move forward with this. Thanks.