diff --git a/app/src/main/java/org/linphone/core/CoreContext.kt b/app/src/main/java/org/linphone/core/CoreContext.kt
index fce3f35c8..d90088e84 100644
--- a/app/src/main/java/org/linphone/core/CoreContext.kt
+++ b/app/src/main/java/org/linphone/core/CoreContext.kt
@@ -499,8 +499,12 @@ class CoreContext @UiThread constructor(val context: Context) : HandlerThread("C
     fun postOnCoreThread(
         @WorkerThread lambda: (core: Core) -> Unit
     ) {
-        coreThread.post {
-            lambda.invoke(core)
+        if (::coreThread.isInitialized) {
+            coreThread.post {
+                lambda.invoke(core)
+            }
+        } else {
+            Log.e("$TAG Core's thread not initialized yet!")
         }
     }
 
@@ -509,9 +513,13 @@ class CoreContext @UiThread constructor(val context: Context) : HandlerThread("C
         @WorkerThread lambda: (core: Core) -> Unit,
         delay: Long
     ) {
-        coreThread.postDelayed({
-            lambda.invoke(core)
-        }, delay)
+        if (::coreThread.isInitialized) {
+            coreThread.postDelayed({
+                lambda.invoke(core)
+            }, delay)
+        } else {
+            Log.e("$TAG Core's thread not initialized yet!")
+        }
     }
 
     @AnyThread
diff --git a/app/src/main/java/org/linphone/ui/assistant/fragment/PermissionsFragment.kt b/app/src/main/java/org/linphone/ui/assistant/fragment/PermissionsFragment.kt
index 73742369f..562ae8936 100644
--- a/app/src/main/java/org/linphone/ui/assistant/fragment/PermissionsFragment.kt
+++ b/app/src/main/java/org/linphone/ui/assistant/fragment/PermissionsFragment.kt
@@ -148,12 +148,20 @@ class PermissionsFragment : GenericFragment() {
                 if (core.accountList.isNotEmpty()) {
                     coreContext.postOnMainThread {
                         Log.w("$TAG At least one account was found, leaving assistant")
-                        requireActivity().finish()
+                        try {
+                            requireActivity().finish()
+                        } catch (ise: IllegalStateException) {
+                            Log.e("$TAG Failed to finish activity: $ise")
+                        }
                     }
                 } else {
                     coreContext.postOnMainThread {
                         Log.w("$TAG No account was found, going to landing fragment")
-                        goToLoginFragment()
+                        try {
+                            goToLoginFragment()
+                        } catch (ise: IllegalStateException) {
+                            Log.e("$TAG Failed to navigate to login fragment: $ise")
+                        }
                     }
                 }
             }