Horde Blacklist Filter Does Not Work

After Blacklisting junk mail I pick the Filter icon at the top of the menu (Horde Mail) but nothing happens. It did function for a while whereas it would delete the files from the list that I had just blacklisted.

I know the blacklist is adding these files to the list as I have checked but the filter button is completely non-responsive. Can someone tell me how to get this filter button working again please?

I am currently running WHM 10.8.0/cPanel 10.8.1-R30 and I have my own server. This is not a shared account.

Thanks for any help...

 

Is there anyone that can help me with this? I have run several searches looking for a situation as mine but could find one. This is the only reason I have posted this. Please, any help would be appreciated...