Cannot set properties of undefine

[ahmaddMahd]

excuse me when I use vue-session I always caught an error when I try to use it . The error on console says
Cannot set properties of undefined (setting '$session')

I already did npm i vue-session
I use the vue session on my create app but the error persist, is this a bug?

import VueSession from 'vue-session'

import './assets/main.css'

const app = createApp(App)
app.use(createPinia())
app.use(router)
app.use(VueSession)