maybe this

middleware/isLoggedIn.global.ts

@@ -3,20 +3,18 @@ export default defineNuxtRouteMiddleware(async (to, from) => {
 	if (to.fullPath !== "/stundenplan") {
 		return true
 	}
-
+	console.log(from.fullPath == "/stundenplan")
 	const username = useCookie("username")
 	const password = useCookie("password")
 	const isLoggedIn = useState("isLoggedIn", (() => false) as () => boolean)
 
-	if (from.fullPath === "/stundenplan") {
+	if (from.fullPath == "/stundenplan") {
 		try {
 			const test_url = `https://corsproxy.io/?https%3A%2F%2Fselfservice.campus-dual.de%2Fdash%2Fgetcp%3Fuser%3D${username.value}%26hash%3D${password.value}`
 			const response = await $fetch(test_url)
 			isLoggedIn.value = !!(response == 0)
-			return true
 		} catch (error) {
 			isLoggedIn.value = false
-			return
 		}
 	}