Try going to an open WiFi location (an AP without any security password). See if it can connect to it (altering your AP settings; going to McDonalds or Starbucks Coffee house etc...)
If it does work then you'll need to check the case of the password as upper & lower case are different here (even unicode characters). Also make sure the password is not overly long as some devices can't parse the key longer that 10 digits/characters.
Next check what security option you are using on the AP and make sure your device can do it. As an example some older devices can't to WPA 2.