diff --git a/src/local.c b/src/local.c
index 3da1302a..01a1a26a 100644
--- a/src/local.c
+++ b/src/local.c
@@ -384,14 +384,13 @@ server_recv_cb(EV_P_ ev_io *w, int revents)
                         if(setsockopt(remote->fd, IPPROTO_TCP, TCP_FASTOPEN,
                                       &optval, sizeof(optval)) != 0) {
                             ERROR("setsockopt");
-                            err = WSAEOPNOTSUPP;
                             break;
                         }
                         // Load ConnectEx function
                         LPFN_CONNECTEX ConnectEx = winsock_getconnectex();
                         if (ConnectEx == NULL) {
                             LOGE("Cannot load ConnectEx() function");
-                            err = WSAEOPNOTSUPP;
+                            err = WSAENOPROTOOPT;
                             break;
                         }
                         // ConnectEx requires a bound socket
diff --git a/src/server.c b/src/server.c
index a968a2bc..cc361e6b 100644
--- a/src/server.c
+++ b/src/server.c
@@ -530,14 +530,13 @@ connect_to_remote(EV_P_ struct addrinfo *res,
             if(setsockopt(sockfd, IPPROTO_TCP, TCP_FASTOPEN,
                           &optval, sizeof(optval)) != 0) {
                 ERROR("setsockopt");
-                err = WSAEOPNOTSUPP;
                 break;
             }
             // Load ConnectEx function
             LPFN_CONNECTEX ConnectEx = winsock_getconnectex();
             if (ConnectEx == NULL) {
                 LOGE("Cannot load ConnectEx() function");
-                err = WSAEOPNOTSUPP;
+                err = WSAENOPROTOOPT;
                 break;
             }
             // ConnectEx requires a bound socket