diff --git a/src/core/RPCSession.ts b/src/core/RPCSession.ts
index a099c80..8c66044 100644
--- a/src/core/RPCSession.ts
+++ b/src/core/RPCSession.ts
@@ -242,6 +242,7 @@ export class RPCSession {
 
                 reject(new RPCError({
                     errorCode: RPCErrorCode.UNKNOWN_ERROR,
+                    reason: e instanceof Error ? e.message : `${e}`
                 }))
             })
         }