More info please... Has the button stopped working?
Have you excluded the new board URL from your cache plugin? Please find the instruction for your cache plugin and add "*" at the endo of the second forum URL if it's necessary: https://wpforo.com/community/faq/wpforo-and-cache-plugins/#post-37150
Please press F12, open the browser footer tool, switch to Console Tab and find red marked errors. If you see any, take a screenshot and paste it here.
When ı click it ıt doesnt work
Have you excluded the new board URL from your cache plugin? Please find the instruction for your cache plugin and add "*" at the endo of the second forum URL if it's necessary: https://wpforo.com/community/faq/wpforo-and-cache-plugins/#post-37150
Please press F12, open the browser footer tool, switch to Console Tab and find red marked errors. If you see any, take a screenshot and paste it here.
Please answer to @robert questions. That will give us more information to be able to help you.