can’t change GW password in NWadmin

I am using NW5.1 and GroupWise 5.5. For some reasons, after I changed the password under the GW tab in NWadmin, the password never get changed. However, if I logged into Webaccess or use the GW client and changed the password there, it works. Does anyone has an suggestion?

BTW, if I change NDS password in NWadmin, it works immediately, so, I don’t know why this is happening and hope someone can give me an idea. thanks