I have a two month old Schlage door lock recently I went to get a new copy of Schlage keys. I tried it one time it work and a week pass suddenly my new keys doesn't work and even the original key, it won't turn at all. but the inside manual lock works.

The battery pack may be weak. They are set to stay locked as opposed to stay unlocked in case of battery failure.

Not being able to use the key is an issue in its own right. You would need a locksmith to solve that one.

https://www.google.com/search?q=Schlage+Smartlock+change+battery

..

https://www.schlage.com/en/home/support/faqs.html

Click on support

https://www.schlage.com/en/home/faq.html?the-schlage-button-won-t-lock-my-lock

Any locksmith can do it,BUT- if you go to hardware store you can find locks that have a number on the front of the box that says something like 'TypeA, or Type B' If you purchase the same lock type with the same number or letter, they will all use the same keys included. It's much cheaper than a locksmith.

Try using powdered graphite in the lock. Available at any key copy place or automotive parts store.

NO, they are not related.

my guess is that during installation the inside lock cylinders were 1/2 or a full rotation more in one direction than the outside cylinders. remove it from the door, assemble it and try it without installing it. If it doesn;'t work, take it back. If it's old, oil it. if that doesn't work- toss it- you've spent an hour on a $15 item.

it sounds as though the linkage that pulls the deadbolt back has disengaged... if you undo the screws from the inside of the door and remove the manual knob there will be 2 more screws holding the key lock to the door. A thin flat bar is attached to the key lock that goes through the deadbolt and into the manual knob. This bar turns with the key, sliding the bolt on its track to lock and unlock the door. Once the lock is apart check the key in the lock to see if the bar turns when the key does. then see if there is anything that may be obstructing the deadbolt from sliding. The locks are pretty indestructible so if there is a problem it may have been from the install... perhaps the door is to wide for the lock to engage properly and the lock worked loose in the 6 months that it worked.

can be easy as wd-40 squirt of oil. try that first... then on to more drastic measures

Make sure that the tang from the lock side actually engage the mechanism in other side of the door. If the tang is too short or not engaged the lock will not work. Also check that the two screws connecting the lock to the other side is actually tight.

I have the same/similar problem. I called the company 888 number. The customer rep promised to send me a new one. good luck