Password Lock doesn’t lead to download

I just posted this topic to the official WordPress forum, but I think to get better assist direct at the publishers forum, so I copy my request
Hi all,
I just installed WP Download Manager Free and put a download online.
This works fine as long as the password lock is disabled.
As soon as I enable password lock and enter a password, update the page, it doesn´t download any longer.
It shows all the fields like enter password and submit, but no matter which password I enter, nothing happens. It just returns to my start page without any message.
How can I find out the reason? I already tried several settings like disabling css and the other options or disabling resuming downloads. Nothing really helps.
As soon as I clear the password field of the download and disable Password Lock again, I am able to download again.
Any advice appreciated.
Thanks
Stefan

Hi Shahjada,

as this is my company´s site I am not allowed to give you wordpress admin rights, unfortunately.
Trying to figure out myself how to fix it, has something to do with our style sheet most probably.

Regards,
Stefan