Board URL currently has /forum at the end of it. This can be fixed with the DNS using CNAME. If this is already set up then the issue is that the boards are in a folder in the subdomains folder, Move the files from the board
Subdomain>Boards Folder>Boards Files*
Please move Board Files, into Subdomain, removing the folder the files were originally in.
This should fix the ending
at the end of the link.
:Hope i helped, thanks