Are you running OONI Probe Desktop 3.5.0 or 3.5.1? 

Unfortunately the auto-updater broke in those versions. 

Please update to OONI Probe Desktop 3.5.2 by downloading and re-installing the app from our website: https://ooni.org/install/desktop

Thank you, and apologies for the inconvenience.

Warmly,

OONI team.