Hi,
This could be a simple configuration issue. First, is your Keylab Essential correctly set on the MIDI setup of FL Studio ? It should be the same as the first attached screenshot.
Then when you insert AnalogLab 2 inside Fl Studio, click on the "Detailed settings" on the upper left corner, go to the VST Wrapper Settings (2nd icon), then set Input port to 1.
I hope it will solve your issue.
Regards,
Matthieu