diff --git a/core/src/main/scala/org/apache/spark/rpc/netty/NettyRpcEnv.scala b/core/src/main/scala/org/apache/spark/rpc/netty/NettyRpcEnv.scala
index f82fd4eb5756d..de3db6ba624f8 100644
--- a/core/src/main/scala/org/apache/spark/rpc/netty/NettyRpcEnv.scala
+++ b/core/src/main/scala/org/apache/spark/rpc/netty/NettyRpcEnv.scala
@@ -232,7 +232,7 @@ private[netty] class NettyRpcEnv(
     val timeoutCancelable = timeoutScheduler.schedule(new Runnable {
       override def run(): Unit = {
         promise.tryFailure(
-          new TimeoutException("Cannot receive any reply in ${timeout.duration}"))
+          new TimeoutException(s"Cannot receive any reply in ${timeout.duration}"))
       }
     }, timeout.duration.toNanos, TimeUnit.NANOSECONDS)
     promise.future.onComplete { v =>