Oh, sorry, we did not use permalinks feature. Thanks for your quick response.
I am using WP3.3.2, I am afraid latest version is not compatible my wordpress version. What do you think?
This issue appear after I checked “Enable (or Disable) The User Management Feature” option with three options:
1. set “Specify How Many Hours After Inactivity To Automatically Logout User” from 0 to 10
2. checked “Locks A User Session To IP address” option
3. set “Limit Simultaneous Sessions For The Same Username” from 0 to 6
