How to skip / at the end of the domain name

Hi all

How can I do this? I want my domain name to be like
www.domainname.com/foldername
when I enter www.domainname.com/foldername it is showing as

“Bad Request”
Your browser sent a request that this server could not understand.

when I add ‘/’ to the above url its working fine.
www.domainname.com/foldername/
Please help me to fix above issue.

Thanks
Kiran.