First of all, check if Skybrush Server is up and running by checking the Server connection widget color (should be green). Move your mouse over it to get detailed info about the server connection.
If the connection is OK and drones are still not visible, double check all wifi settings. See the wifi setup section in the Hardware setup tutorial for details.
This can happen on Arducopter-based drones where the light module is driven by servo outputs, one for each color channel. To setup your channels properly, setup the
SERVOx_FUNCTION ArduCopter parameters with values 107, 108 and 109 for the red, green and blue channels, respectively. An example:
SERVO9_FUNCTION,107 SERVO10_FUNCTION,108 SERVO11_FUNCTION,109
In the example above servo 9 is used to drive the red channel (107), servo 10 drives the green channel (108) and servo 11 drives the blue channel (109).
There can be hundreds of reasons why drones do not pass prearm checks. Use the PREFLIGHT tab in the Properties dialog to get detailed info about preflight errors.
In case of severe errors check or calibrate your indicated system component.
If you feel that your current error is not severe, in case of ArduCopter-based drones you can try to change the value of the
ARMING_CHECK parameter to skip certain preflight tests.
Some (usually cheap or not original) GPS modules are not fully ArduCopter compatible and thus ArduCopter cannot configure them automatically at startup. In this case it can happen that the GPS seems to be working, but some important navigation messages are lacking. One of this cases is when there is 2D fix but not 3D fix as the GPS timestamp is missing either the time-of-week or the week number component. In such cases contact your HW manufacturer or consider changing to a more reliable HW source.
On Arducopter based drones geofence upload will fail with MAVLink 1 protocol even when other parts of the communication seem flawless. Always use MAVLink 2 protocol an all MAVLink channels to avoid this and other possible unexpected communication problems.
To change MAVLink protocol on your wifi communication channel, use the
SERIALx_PROTOCOL ArduCopter parameter with the value of 2 instead of 1 (x should be replaced by the number of the channel that is associated with your wifi link).
Skybrush Live uses only open source satellite tiles on the Base Map Layer, such as ones from OpenStreetMap, MapBox or Maptiler. If you wish to use other tile sources at your own legal responsibility, enable the Tile Server Layer from the Layers panel and add your convenient WMS, XYZ or TILECACHE tile URL.