[General] faced issue when change theme

[aliraza121111]

sir i am change theme at my forum when i am choose defualt theme then my plugin are not working why?

[.m.]

when you install a new theme, plugins related codes need to be added to relevant templates.
in general, deactivating & re-activating all plugins one by one makes required changes to work.
some plugins might lose their settings by deactivating and they need to be configured again