diff --git a/monext/src/main/kotlin/com/monext/sdk/internal/data/sessionstate/ActiveWaiting.kt b/monext/src/main/kotlin/com/monext/sdk/internal/data/sessionstate/ActiveWaiting.kt
index b68c9c6..3ce51f9 100644
--- a/monext/src/main/kotlin/com/monext/sdk/internal/data/sessionstate/ActiveWaiting.kt
+++ b/monext/src/main/kotlin/com/monext/sdk/internal/data/sessionstate/ActiveWaiting.kt
@@ -9,5 +9,5 @@ internal data class ActiveWaiting(
     val cardCode: String,
     val contractNumber: String,
     val walletCardIndex: Int,
-    val merchantReturnUrl: String
+    val merchantReturnUrl: String?
 )
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