Random/unstable wifi connection to simulated Bebop2

Product: [Bebop/Bebop2]
Product version: [X.X.X]
SDK version: [X.X.X]
Use of libARController: [YES/NO] (Only for ARSDK)
SDK platform: [iOS/Android/Unix/Python…]
Reproductible with the official app: [YES/NO/Not tried]
I am running sphinx 1.8 under ubuntu 18.04 native on a MacbookPro (i7, 8 core, 16G ram). Wifi connection is setup via an EDUP dongle. The interface name is fixed at wlan0.
I have been simulating a Bebop2 (which is actually my own drone…), without front camera, and I did manage to get my skycontroller 2 connected and make the simulated drone fly.
Connecting to the simulated drone does always take long, several minutes.
Yet, the possibility to get the skycontroller (or also an iPhone with Freeflight) connected is random: sometimes it works fine, sometimes it just does not connect at all. I need to power off the mac and restart everything, and then I might connect - but sometimes I need to go through the process a few times.
By the way, using my iphone I can see the wifi access-point generated by the simulator, and I can connect to the generated network, but Freeflight will not connect.
Any idea on what I should check out, look at, or try and do, to be able to use the simulator in a more reliable way? Is there any sphinx debug mode I can use to check wifi connection?