diff --git a/src/main/kotlin/org/gitanimals/coupon/controller/response/CouponResponse.kt b/src/main/kotlin/org/gitanimals/coupon/controller/response/CouponResponse.kt
index b8c50a6..16ce976 100644
--- a/src/main/kotlin/org/gitanimals/coupon/controller/response/CouponResponse.kt
+++ b/src/main/kotlin/org/gitanimals/coupon/controller/response/CouponResponse.kt
@@ -2,6 +2,7 @@ package org.gitanimals.coupon.controller.response
 
 import org.gitanimals.coupon.domain.Coupon
 import java.time.LocalDateTime
+import java.time.ZoneOffset
 
 data class CouponResponse(
     val id: String,
@@ -16,7 +17,7 @@ data class CouponResponse(
                 id = coupon.id.toString(),
                 userId = coupon.userId.toString(),
                 code = coupon.code,
-                usedAt = LocalDateTime.from(coupon.usedAt),
+                usedAt = LocalDateTime.ofInstant(coupon.usedAt, ZoneOffset.UTC),
             )
     }
 }
diff --git a/src/main/kotlin/org/gitanimals/coupon/infra/RestIdentityApi.kt b/src/main/kotlin/org/gitanimals/coupon/infra/RestIdentityApi.kt
index cd65c5c..ff03382 100644
--- a/src/main/kotlin/org/gitanimals/coupon/infra/RestIdentityApi.kt
+++ b/src/main/kotlin/org/gitanimals/coupon/infra/RestIdentityApi.kt
@@ -16,8 +16,11 @@ class RestIdentityApi : IdentityApi {
             .uri("/users")
             .header(HttpHeaders.AUTHORIZATION, token)
             .exchange { _, response ->
-                response.bodyTo(UserResponse::class.java)
-                    ?: throw IllegalArgumentException("Authorization failed")
+                runCatching {
+                    response.bodyTo(UserResponse::class.java)
+                }.getOrElse {
+                    throw IllegalArgumentException("Authorization failed", it)
+                }
             }
     }
 }
diff --git a/src/main/kotlin/org/gitanimals/gotcha/infra/RestRenderApi.kt b/src/main/kotlin/org/gitanimals/gotcha/infra/RestRenderApi.kt
index 21482d9..87e0615 100644
--- a/src/main/kotlin/org/gitanimals/gotcha/infra/RestRenderApi.kt
+++ b/src/main/kotlin/org/gitanimals/gotcha/infra/RestRenderApi.kt
@@ -21,9 +21,16 @@ class RestRenderApi(
             )
             .exchange { _, response ->
                 if (response.statusCode.is2xxSuccessful) {
-                    return@exchange response.bodyTo(object :
-                        ParameterizedTypeReference<Map<String, String>>() {})?.get("id")
-                        ?: throw IllegalStateException("Create persona success but, cannot get persona-id")
+                    return@exchange runCatching {
+                        response.bodyTo(object :
+                            ParameterizedTypeReference<Map<String, String>>() {})?.get("id")
+                    }.getOrElse {
+                        throw IllegalStateException(
+                            "Create persona success but, cannot get persona-id", it
+                        )
+                    } ?: throw IllegalStateException(
+                        "Create persona success but, cannot get persona-id cause it's null"
+                    )
                 }
                 throw IllegalArgumentException("Cannot add persona name \"$personaName\" to user")
             }
diff --git a/src/main/kotlin/org/gitanimals/gotcha/infra/RestUserApi.kt b/src/main/kotlin/org/gitanimals/gotcha/infra/RestUserApi.kt
index e68f444..b64ed1d 100644
--- a/src/main/kotlin/org/gitanimals/gotcha/infra/RestUserApi.kt
+++ b/src/main/kotlin/org/gitanimals/gotcha/infra/RestUserApi.kt
@@ -17,8 +17,11 @@ class RestUserApi(
             .uri("/users")
             .header(HttpHeaders.AUTHORIZATION, token)
             .exchange { _, response ->
-                response.bodyTo(UserResponse::class.java)
-                    ?: throw IllegalArgumentException("Authorization failed")
+                runCatching {
+                    response.bodyTo(UserResponse::class.java)
+                }.getOrElse {
+                    throw IllegalArgumentException("Authorization failed", it)
+                }
             }
     }