diff --git a/src/main/kotlin/dev/usbharu/hideout/activitypub/domain/model/Undo.kt b/src/main/kotlin/dev/usbharu/hideout/activitypub/domain/model/Undo.kt
index 178373fd..6f27026e 100644
--- a/src/main/kotlin/dev/usbharu/hideout/activitypub/domain/model/Undo.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/activitypub/domain/model/Undo.kt
@@ -11,7 +11,7 @@ open class Undo(
     override val id: String,
     @JsonDeserialize(using = ObjectDeserializer::class)
     @JsonProperty("object") val apObject: Object,
-    val published: String
+    val published: String?
 ) : Object(add(type, "Undo")), HasId, HasActor {
 
     override fun equals(other: Any?): Boolean {
@@ -21,20 +21,20 @@ open class Undo(
 
         other as Undo
 
-        if (apObject != other.apObject) return false
-        if (published != other.published) return false
         if (actor != other.actor) return false
         if (id != other.id) return false
+        if (apObject != other.apObject) return false
+        if (published != other.published) return false
 
         return true
     }
 
     override fun hashCode(): Int {
         var result = super.hashCode()
-        result = 31 * result + apObject.hashCode()
-        result = 31 * result + published.hashCode()
         result = 31 * result + actor.hashCode()
         result = 31 * result + id.hashCode()
+        result = 31 * result + apObject.hashCode()
+        result = 31 * result + (published?.hashCode() ?: 0)
         return result
     }
 
@@ -43,7 +43,7 @@ open class Undo(
                 "actor='$actor', " +
                 "id='$id', " +
                 "apObject=$apObject, " +
-                "published='$published'" +
+                "published=$published" +
                 ")" +
                 " ${super.toString()}"
     }
diff --git a/src/main/kotlin/dev/usbharu/hideout/activitypub/service/inbox/InboxJobProcessor.kt b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/inbox/InboxJobProcessor.kt
index fbe38266..48bbbfe1 100644
--- a/src/main/kotlin/dev/usbharu/hideout/activitypub/service/inbox/InboxJobProcessor.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/inbox/InboxJobProcessor.kt
@@ -1,5 +1,6 @@
 package dev.usbharu.hideout.activitypub.service.inbox
 
+import com.fasterxml.jackson.core.JsonParseException
 import com.fasterxml.jackson.databind.ObjectMapper
 import com.fasterxml.jackson.module.kotlin.readValue
 import dev.usbharu.hideout.activitypub.domain.model.objects.Object
@@ -119,7 +120,12 @@ class InboxJobProcessor(
             throw IllegalStateException("ActivityPubProcessor not found. type: ${param.type}")
         }
 
-        val value = objectMapper.treeToValue(jsonNode, activityPubProcessor.type())
+        val value = try {
+            objectMapper.treeToValue(jsonNode, activityPubProcessor.type())
+        } catch (e: JsonParseException) {
+            logger.warn("Invalid JSON\n\n{}\n\n", jsonNode.toPrettyString())
+            throw e
+        }
         activityPubProcessor.process(ActivityPubProcessContext(value, jsonNode, httpRequest, signature, verify))
 
         logger.info("SUCCESS Process inbox. type: {}", param.type)
diff --git a/src/test/kotlin/dev/usbharu/hideout/activitypub/domain/model/UndoTest.kt b/src/test/kotlin/dev/usbharu/hideout/activitypub/domain/model/UndoTest.kt
index ea279694..ad111d27 100644
--- a/src/test/kotlin/dev/usbharu/hideout/activitypub/domain/model/UndoTest.kt
+++ b/src/test/kotlin/dev/usbharu/hideout/activitypub/domain/model/UndoTest.kt
@@ -71,4 +71,25 @@ class UndoTest {
         val undo = ActivityPubConfig().objectMapper().readValue(json, Undo::class.java)
         println(undo)
     }
+
+    @Test
+    fun MastodonのUndoのデシリアライズができる() {
+        //language=JSON
+        val json = """{
+  "@context" : "https://www.w3.org/ns/activitystreams",
+  "id" : "https://kb.usbharu.dev/users/usbharu#follows/12/undo",
+  "type" : "Undo",
+  "actor" : "https://kb.usbharu.dev/users/usbharu",
+  "object" : {
+    "id" : "https://kb.usbharu.dev/0347b269-4dcb-4eb1-b8c4-b5f157bb6957",
+    "type" : "Follow",
+    "actor" : "https://kb.usbharu.dev/users/usbharu",
+    "object" : "https://test-hideout.usbharu.dev/users/testuser15"
+  }
+}""".trimIndent()
+
+        val undo = ActivityPubConfig().objectMapper().readValue<Undo>(json, Undo::class.java)
+
+        println(undo)
+    }
 }