diff --git a/bot/admin/web/src/app/core-nlp/state.service.ts b/bot/admin/web/src/app/core-nlp/state.service.ts
index 3f834f0692..62eb56d1ee 100644
--- a/bot/admin/web/src/app/core-nlp/state.service.ts
+++ b/bot/admin/web/src/app/core-nlp/state.service.ts
@@ -81,7 +81,7 @@ export class StateService implements AuthListener {
   }
 
   static normalizeLocaleCode(code: string): string {
-    return code.split('_')[0];
+    return code ? code.split(/[-_]/)[0] : code;
   }
 
   constructor(private auth: AuthService, private settings: SettingsService) {
diff --git a/bot/connector-rest-client/src/main/kotlin/ConnectorRestClient.kt b/bot/connector-rest-client/src/main/kotlin/ConnectorRestClient.kt
index f68dcd1629..ca3eaee8b2 100644
--- a/bot/connector-rest-client/src/main/kotlin/ConnectorRestClient.kt
+++ b/bot/connector-rest-client/src/main/kotlin/ConnectorRestClient.kt
@@ -76,6 +76,6 @@ class ConnectorRestClient(
         locale: Locale,
         query: ClientMessageRequest,
     ): Response<ClientMessageResponse> {
-        return getService(path).talk(locale, query).execute()
+        return getService(path).talk(locale.toLanguageTag(), query).execute()
     }
 }
diff --git a/bot/connector-rest-client/src/main/kotlin/ConnectorRestService.kt b/bot/connector-rest-client/src/main/kotlin/ConnectorRestService.kt
index a424efb064..9b1cf09037 100644
--- a/bot/connector-rest-client/src/main/kotlin/ConnectorRestService.kt
+++ b/bot/connector-rest-client/src/main/kotlin/ConnectorRestService.kt
@@ -30,7 +30,7 @@ import java.util.Locale
 interface ConnectorRestService {
     @POST("{locale}")
     fun talk(
-        @Path("locale") locale: Locale,
+        @Path("locale") locale: String,
         @Body request: ClientMessageRequest,
     ): Call<ClientMessageResponse>
 }
diff --git a/bot/connector-rest/src/main/kotlin/RestConnector.kt b/bot/connector-rest/src/main/kotlin/RestConnector.kt
index 0a6b775568..b5c1572e22 100644
--- a/bot/connector-rest/src/main/kotlin/RestConnector.kt
+++ b/bot/connector-rest/src/main/kotlin/RestConnector.kt
@@ -205,4 +205,4 @@ class RestConnector(
                 else -> getTargetConnector(targetConnectorType)?.toConnectorMessage(message)?.invoke(this) ?: emptyList()
             }
         }
-}
+}
\ No newline at end of file