Hello,I made a flight from KFLL to KTPA just now and for some reason, I can't switch on the A/T... everytime I do, the A/T error light flases... not sure whats going on, but its really annoying, and I have no clue why its doing that! i've flown the 737 many times and never had this problem before... its 12.30am so maybe i'm just having a brain #### and forgetting something... can anyone help me out? lol thx :)

Most common reason for this is the engine generators are off line. See http://ops.precisionmanuals.com/wiki/PMDG_..._will_not_latch