diff --git a/app/src/main/java/io/timelimit/android/ui/model/State.kt b/app/src/main/java/io/timelimit/android/ui/model/State.kt
index e19784e..f31f231 100644
--- a/app/src/main/java/io/timelimit/android/ui/model/State.kt
+++ b/app/src/main/java/io/timelimit/android/ui/model/State.kt
@@ -262,7 +262,7 @@ sealed class State (val previous: State?): Serializable {
             val previousSelectMode: SelectMode,
             val currentDialog: Dialog? = null
         ): Setup(previous = previousSelectMode) {
-            sealed class Dialog
+            sealed class Dialog: Serializable
 
             data class SystemPermissionDialog(val permission: SystemPermission): Dialog()
             object ParentKeyDialog: Dialog()
diff --git a/app/src/main/java/io/timelimit/android/ui/model/mailauthentication/MailAuthentication.kt b/app/src/main/java/io/timelimit/android/ui/model/mailauthentication/MailAuthentication.kt
index d41910c..6162227 100644
--- a/app/src/main/java/io/timelimit/android/ui/model/mailauthentication/MailAuthentication.kt
+++ b/app/src/main/java/io/timelimit/android/ui/model/mailauthentication/MailAuthentication.kt
@@ -31,6 +31,7 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.launch
 import java.io.IOException
+import java.io.Serializable
 
 object MailAuthentication {
     sealed class State: java.io.Serializable {
@@ -120,7 +121,7 @@ object MailAuthentication {
         data class Error(val dialog: ErrorDialog, val close: () -> Unit)
     }
 
-    sealed class ErrorDialog {
+    sealed class ErrorDialog: Serializable {
         object RateLimit: ErrorDialog()
         object BlockedMailServer: ErrorDialog()
         object MailAddressNotAllowed: ErrorDialog()