diff --git a/backend/src/main/kotlin/ru/posidata/backend/service/TelegramAuthService.kt b/backend/src/main/kotlin/ru/posidata/backend/service/TelegramAuthService.kt
index 7e4b233..072231f 100644
--- a/backend/src/main/kotlin/ru/posidata/backend/service/TelegramAuthService.kt
+++ b/backend/src/main/kotlin/ru/posidata/backend/service/TelegramAuthService.kt
@@ -11,7 +11,7 @@ class TelegramAuthService(
     @Value("\${telegram.bot.token}") private val telegramToken: String,
 ) {
     fun isValidHash(parsedData: Map<String, String>, hash: String): Boolean {
-        val dataKeys = parsedData.keys.filter { it != "hash" }.sorted()
+        val dataKeys = parsedData.keys.filter { it != "hash" }.filter { parsedData[it] != "undefined" }.sorted()
         val items = dataKeys.map { key -> "$key=${parsedData[key]}" }
         val dataCheckString = items.joinToString("\n")
 
diff --git a/frontend/src/jsMain/kotlin/ru/posidata/views/main/QuestionCard.kt b/frontend/src/jsMain/kotlin/ru/posidata/views/main/QuestionCard.kt
index 69e77f1..3b432c2 100644
--- a/frontend/src/jsMain/kotlin/ru/posidata/views/main/QuestionCard.kt
+++ b/frontend/src/jsMain/kotlin/ru/posidata/views/main/QuestionCard.kt
@@ -52,7 +52,7 @@ val questionCard = FC<QuestionCard> { props ->
 
             when {
                 response.ok -> props.setUser(response.decodeFromJsonString<UserForSerializationDTO>())
-                else -> window.alert("Failed to login with telegram")
+                else -> window.alert("Failed to validate with telegram")
             }
         }
     }
diff --git a/frontend/src/jsMain/kotlin/ru/posidata/views/main/ResultCard.kt b/frontend/src/jsMain/kotlin/ru/posidata/views/main/ResultCard.kt
index a8b5f7d..618df6c 100644
--- a/frontend/src/jsMain/kotlin/ru/posidata/views/main/ResultCard.kt
+++ b/frontend/src/jsMain/kotlin/ru/posidata/views/main/ResultCard.kt
@@ -49,7 +49,7 @@ val resultCard = FC<ResultProps> { props ->
 
             when {
                 response.ok -> props.setUser(response.decodeFromJsonString<UserForSerializationDTO>())
-                else -> window.alert("Failed to login with telegram")
+                else -> window.alert("Failed to validate with telegram")
             }
         }
     }
diff --git a/frontend/src/jsMain/kotlin/ru/posidata/views/main/Welcome.kt b/frontend/src/jsMain/kotlin/ru/posidata/views/main/Welcome.kt
index 6d4a765..a67224a 100644
--- a/frontend/src/jsMain/kotlin/ru/posidata/views/main/Welcome.kt
+++ b/frontend/src/jsMain/kotlin/ru/posidata/views/main/Welcome.kt
@@ -39,13 +39,14 @@ val welcomeCard = FC<WelcomeCardProps> { props ->
                 response.ok -> {
                     props.setUser(response.decodeFromJsonString<UserForSerializationDTO>())
                 }
-                else -> window.alert("Failed to login with telegram")
+                else -> window.alert("Failed to validate with telegram")
             }
         }
         props.setSelection(Selection.QUESTION)
     }
 
     // just a small test
+/*
     div {
         button {
             onClick = {
@@ -71,6 +72,7 @@ val welcomeCard = FC<WelcomeCardProps> { props ->
             }
         }
     }
+*/
 
 
     div {