roundcube password plugin: error 600

[faryal]

i have install xampp , hmailserver and roundecube. i have followed this tutorial to integrate roundcube mail https://www.youtube.com/watch?v=DekIO0IIwLQ.
the problem is, i cannot change the password it gives error SERVICE CURRENTLY NOT AVAILABLE! Error No. [600]
i cannot find this error and its soultion on internet.
kindly guide to solve this issue.