diff --git a/backend/services/mining-blockchain-service/src/infrastructure/mpc/mpc-signing.client.ts b/backend/services/mining-blockchain-service/src/infrastructure/mpc/mpc-signing.client.ts
index 9022a4d1..17a9d12d 100644
--- a/backend/services/mining-blockchain-service/src/infrastructure/mpc/mpc-signing.client.ts
+++ b/backend/services/mining-blockchain-service/src/infrastructure/mpc/mpc-signing.client.ts
@@ -224,7 +224,7 @@ export class MpcSigningClient {
         message_hash?: string;
       }>(
         createUrl,
-        { username, message_hash: messageHash },
+        { username, message_hash: messageHash.startsWith('0x') ? messageHash.slice(2) : messageHash },
         { headers, timeout: 30000 },
       ),
     );