diff --git a/src/tls.cpp b/src/tls.cpp
index 61d01fff1..3ad43e0a0 100644
--- a/src/tls.cpp
+++ b/src/tls.cpp
@@ -817,6 +817,9 @@ static int connTLSWrite(connection *conn_, const void *data, size_t data_len) {
     tls_connection *conn = (tls_connection *) conn_;
     int ret, ssl_err;
 
+    if (data_len == 0)
+        return 0;
+
     if (conn->c.state != CONN_STATE_CONNECTED) return -1;
     ERR_clear_error();
     ret = SSL_write(conn->ssl, data, data_len);