BuddyPress.org

I have a user who keeps being unable to access their account. They get a message that they are using incorrect passwords. I have tried:

Putting in new passwords from the administrative area (multiple times)
Resetting their passwords using “forgotten password” (multiple times)
I have checked the database and the account looks to be normal. I have checked the database to be sure the password changes when we change it – and it does.
I deleted the account and opened a new one. That worked for a while, but then they got locked out again with the same message.
The only clue I have is that if I go into “users” and go to their account and click “log out everywhere”, the account seems to open again.

Please help – he is a paying customer and I have had to refund him a months fee because of this problem. (I also had a previous user with the same problem – although with their new account that seems to be OK now).

As admin I am able to login OK.
Other users can also login OK.

I am using WPLMS and buddypress 2.7.2
WordPress 4.6.1 running WPLMS theme.
My site is http://www.mashauri.org