diff --git a/src/inet/UDPEndPointImplSockets.cpp b/src/inet/UDPEndPointImplSockets.cpp
index 5c9748d..b681a56 100644
--- a/src/inet/UDPEndPointImplSockets.cpp
+++ b/src/inet/UDPEndPointImplSockets.cpp
@@ -469,7 +469,14 @@
         {
             return CHIP_ERROR_POSIX(errno);
         }
-        ReturnErrorOnFailure(static_cast<System::LayerSockets *>(&GetSystemLayer())->StartWatchingSocket(mSocket, &mWatch));
+        CHIP_ERROR err = static_cast<System::LayerSockets *>(&GetSystemLayer())->StartWatchingSocket(mSocket, &mWatch);
+        if (err != CHIP_NO_ERROR)
+        {
+            // Our mWatch is not valid; make sure we never use it.
+            close(mSocket);
+            mSocket = kInvalidSocketFd;
+            return err;
+        }
 
         mAddrType = addressType;