bbPress.org

Hello,
I have a problem with bbpress.
a couple of days ago a problem started with making accounts on my site.
When a new user is making an account he receives an e-mail with an activation link in that mail.
When he clicks that mail he is comming on a page with an box where he needs to add an activation code.
But in the mail there is no activation code. only a link like: http://website.nl/activate/79d6b96dbaaf352d993dafae852f9b26/

So looks like the account should be activated direct from that link but this is not working.
Also when i enter the code 79d6b96dbaaf352d993dafae852f9b26 again in the field where is aked for activation code this is not working.
So people can not make new accounts at this moment on my website.
Who can help me solve this?

Kind regards

Daniel

latest wordpress and bbpress version installed