diff --git a/drivers/unix/tcp_server_posix.cpp b/drivers/unix/tcp_server_posix.cpp
index f91ad36ef98d..dfcf479fc0fe 100644
--- a/drivers/unix/tcp_server_posix.cpp
+++ b/drivers/unix/tcp_server_posix.cpp
@@ -93,6 +93,9 @@ Error TCPServerPosix::listen(uint16_t p_port,const List<String> *p_accepted_host
 			close(sockfd);
 			ERR_FAIL_V(FAILED);
 		};
+	}
+	else {
+		return ERR_ALREADY_IN_USE;
 	};
 
 	if (listen_sockfd != -1) {
diff --git a/platform/windows/tcp_server_winsock.cpp b/platform/windows/tcp_server_winsock.cpp
index 7b35bcc7ad15..e77ca6feaa90 100644
--- a/platform/windows/tcp_server_winsock.cpp
+++ b/platform/windows/tcp_server_winsock.cpp
@@ -86,6 +86,9 @@ Error TCPServerWinsock::listen(uint16_t p_port,const List<String> *p_accepted_ho
 			closesocket(sockfd);
 			ERR_FAIL_V(FAILED);
 		};
+	}
+	else {
+		return ERR_ALREADY_IN_USE;
 	};
 
 	if (listen_sockfd != INVALID_SOCKET) {