Password reset issue on my latest version

Hi, I am Israel Roy from Sri Lanka. I have installed the latest OwnCloud version, which is 10.12.1.
My problem is that I created a new user, and he changed his password. Due to some reason, he forgot his password and requested to reset it, but as an admin, I tried the reset option, but the password wouldn’t reset.

Is there any advice on how I can resolve this issue?