Vbulletin, registered users unable to post

[kenitra]

My registered users are receiving the e-mail confirmation but when they confirm their e-mail, they are still not able to post, they receive the following error:

[you do not have permission to access this page. This could be due to one of several reasons:
Your user account may not have sufficient privileges to access this page. Are you trying to edit someone else's post, access administrative features or some other privileged system?
If you are trying to post, the administrator may have disabled your account, or it may be awaiting activation. ]
See screenshot: Attachment 71917

I checked my admin page, forums permission is fine but found that several are showing on that these users are still waiting on email confirmation but they already confirmed their email address.
See screenshot Attachment 71918
can anyone help?

Thanks!