First, thanx for the reply.
After your proposal, I decided checking the HTML and I found some errors about CSP so the two lines I add on my kibana.yml just delete csp errors in the browser debugger.
I found interresting information about browser version and CSP on this website :
And as wee can see, wroker-src need firefox 58+ (my initial errror is about worker-src)
So I upgrade my Firefox to 78.4.0 and I no longer have problem.
Thx, Cad