diff --git a/actions/admin/challenges.ts b/actions/admin/challenges.ts
index de5073e..268b4d0 100644
--- a/actions/admin/challenges.ts
+++ b/actions/admin/challenges.ts
@@ -97,7 +97,7 @@ export async function updateChallenge(
   }
 ) {
   try {
-    const session = await checkAdminAccess()
+    await checkAdminAccess()
 
     const challenge = await challengeService.updateChallenge(challengeId, {
       title: data.title,
@@ -128,7 +128,7 @@ export async function updateChallenge(
 
 export async function deleteChallenge(challengeId: string) {
   try {
-    const session = await checkAdminAccess()
+    await checkAdminAccess()
 
     await challengeService.deleteChallenge(challengeId)
 
diff --git a/components/admin/ChallengeManagement.tsx b/components/admin/ChallengeManagement.tsx
index f19e07b..3ec11d2 100644
--- a/components/admin/ChallengeManagement.tsx
+++ b/components/admin/ChallengeManagement.tsx
@@ -196,7 +196,7 @@ export default function ChallengeManagement() {
         {acceptedChallenges.length} défi{acceptedChallenges.length > 1 ? "s" : ""} en attente de validation
         {pendingChallenges.length > 0 && (
           <span className="ml-2">
-            • {pendingChallenges.length} défi{pendingChallenges.length > 1 ? "s" : ""} en attente d'acceptation
+            • {pendingChallenges.length} défi{pendingChallenges.length > 1 ? "s" : ""} en attente d&apos;acceptation
           </span>
         )}
       </div>
@@ -241,7 +241,7 @@ export default function ChallengeManagement() {
                     ? "bg-green-500/20 text-green-400"
                     : "bg-yellow-500/20 text-yellow-400"
                 }`}>
-                  {challenge.status === "ACCEPTED" ? "Accepté" : "En attente d'acceptation"}
+                  {challenge.status === "ACCEPTED" ? "Accepté" : "En attente d&apos;acceptation"}
                 </span>
               </div>
               {challenge.acceptedAt && (
diff --git a/components/challenges/ChallengesSection.tsx b/components/challenges/ChallengesSection.tsx
index da1c6b2..2745bfa 100644
--- a/components/challenges/ChallengesSection.tsx
+++ b/components/challenges/ChallengesSection.tsx
@@ -159,7 +159,7 @@ export default function ChallengesSection({ backgroundImage }: ChallengesSection
   const getStatusLabel = (status: string) => {
     switch (status) {
       case "PENDING":
-        return "En attente d'acceptation";
+        return "En attente d&apos;acceptation";
       case "ACCEPTED":
         return "Accepté - En attente de validation admin";
       case "COMPLETED":
@@ -308,7 +308,7 @@ export default function ChallengesSection({ backgroundImage }: ChallengesSection
         ) : challenges.length === 0 ? (
           <Card variant="dark" className="p-6 text-center">
             <p className="text-gray-400">
-              Vous n'avez aucun défi pour le moment.
+              Vous n&apos;avez aucun défi pour le moment.
             </p>
           </Card>
         ) : (
diff --git a/services/challenges/challenge.service.ts b/services/challenges/challenge.service.ts
index 25512c9..d61c3b9 100644
--- a/services/challenges/challenge.service.ts
+++ b/services/challenges/challenge.service.ts
@@ -4,7 +4,7 @@ import type {
   ChallengeStatus,
   Prisma,
 } from "@/prisma/generated/prisma/client";
-import { ValidationError, NotFoundError, ConflictError } from "../errors";
+import { ValidationError, NotFoundError } from "../errors";
 
 export interface CreateChallengeInput {
   challengerId: string;
@@ -293,13 +293,13 @@ export class ChallengeService {
       updateData.status = data.status;
     }
     if (data.adminId !== undefined) {
-      updateData.adminId = data.adminId;
+      updateData.admin = data.adminId ? { connect: { id: data.adminId } } : { disconnect: true };
     }
     if (data.adminComment !== undefined) {
       updateData.adminComment = data.adminComment;
     }
     if (data.winnerId !== undefined) {
-      updateData.winnerId = data.winnerId;
+      updateData.winner = data.winnerId ? { connect: { id: data.winnerId } } : { disconnect: true };
     }
 
     return prisma.challenge.update({