Im pretty new with this, ive been using my Nexus 5 since January, everything is fine until today, I installed a lockscreen app called AcDisplay, i cant seem to activate it, its asking me to allow it under Device Administrators (Settings> Security) but when it try im being asked to enter a pin code, I dont know if I set a pin code or if I did i cant seem to remember. I tried my lockscreen pincode but its not accepting it. Is there a way to reset the pin? I never had issues with this before, I got an Airdroid app and I can activate it before under the same settings but now Android Device Manager is the only app allowed. Please help me. Im running a customer ROM called Paranoid Saber Droid. Thanks in advance!