logon problems on win2k domain

Hi,

we are running a windows 2000 domain (primary domain controller and backup domain controller) and a bunch of NT clients connecting to it.

For no reason sometimes the clients are not able to logon, especially if we reset the person’s password or force it to be changed on the next logon. There is no clear pattern though.

Have you got any ideas on how to solve this problem? Thank you in advance.