# Connected to voxl-mavlink-server but no messages from PX4

Source: https://forum.modalai.com/topic/2057/connected-to-voxl-mavlink-server-but-no-messages-from-px4
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2023-04-11 10:37:11 UTC by TPSetati
Replies: 1 · Views: 707

## TPSetati · 2023-04-11 10:37:11 UTC

Good day

I am currently having a problem receiving messages from px4 via MAVLINK on my VOXL2 board. I think this started after we tried flying autonomously and there was an FCU: Vision Failure error after takeoff. From there we could not connect to QGC regardless of how many times we ran and restarted the MAVLINK server and voxl-vision-px4. 

Running **voxl-vision-px4 --debug_udp_recv** gives:
![Screenshot from 2023-04-11 11-46-23.png](https://forum.modalai.com/assets/uploads/files/1681207584031-screenshot-from-2023-04-11-11-46-23.png)

## Reply by TPSetati · 2023-04-11 15:08:24 UTC

It seems that the variable **"external_fc"** in *voxl-mavlink-server.conf* kept resetting to true, when it should remain false.