diff --git a/plugins/in_calyptia_fleet/in_calyptia_fleet.c b/plugins/in_calyptia_fleet/in_calyptia_fleet.c
index b7352f7a8e1..0a4100de8e0 100644
--- a/plugins/in_calyptia_fleet/in_calyptia_fleet.c
+++ b/plugins/in_calyptia_fleet/in_calyptia_fleet.c
@@ -605,6 +605,7 @@ static int in_calyptia_fleet_collect(struct flb_input_instance *ins,
     flb_sds_t cfgoldname;
     flb_sds_t cfgcurname;
     flb_sds_t header;
+    flb_sds_t hdr;
     FILE *cfgfp;
     const char *fbit_last_modified;
     int fbit_last_modified_len;
@@ -691,16 +692,16 @@ static int in_calyptia_fleet_collect(struct flb_input_instance *ins,
         }
         header = flb_sds_create_size(4096);
         if (ctx->fleet_name == NULL) {
-            flb_sds_printf(&header,
+            hdr = flb_sds_printf(&header,
                         "[CUSTOM]\n"
-                        "    Name          calyptia\n"
-                        "    api_key       %s\n"
-                        "    fleet_id      %s\n"
-                        "    add_label     fleet_id %s\n"
-                        "    fleet.config_dir    %s\n"
-                        "    calyptia_host %s\n"
-                        "    calyptia_port %d\n"
-                        "    calyptia_tls  %s\n",
+                        "    Name             calyptia\n"
+                        "    api_key          %s\n"
+                        "    fleet_id         %s\n"
+                        "    add_label        fleet_id %s\n"
+                        "    fleet.config_dir %s\n"
+                        "    calyptia_host    %s\n"
+                        "    calyptia_port    %d\n"
+                        "    calyptia_tls     %s\n",
                         ctx->api_key,
                         ctx->fleet_id,
                         ctx->fleet_id,
@@ -710,7 +711,7 @@ static int in_calyptia_fleet_collect(struct flb_input_instance *ins,
                         tls_setting_string(ctx->ins->use_tls)
             );
         } else {
-            flb_sds_printf(&header,
+            hdr = flb_sds_printf(&header,
                         "[CUSTOM]\n"
                         "    Name          calyptia\n"
                         "    api_key       %s\n"
@@ -731,6 +732,17 @@ static int in_calyptia_fleet_collect(struct flb_input_instance *ins,
                         tls_setting_string(ctx->ins->use_tls)
             );
         }
+        if (hdr == NULL) {
+            fclose(cfgfp);
+            goto http_error;
+        }
+        if (ctx->machine_id) {
+            hdr = flb_sds_printf(&header, "    machine_id %s\n", ctx->machine_id);
+            if (hdr == NULL) {
+                fclose(cfgfp);
+                goto http_error;
+            }
+        }
         fwrite(header, strlen(header), 1, cfgfp);
         flb_sds_destroy(header);
         fwrite(data, client->resp.payload_size, 1, cfgfp);