Hello Stefano, and thanks for your quick answer.
When getting to some other section of the general board, and back to the newsletter board, it shows that the letter is sent, but very slowly. After 2 hours, it did only 73% of 270 subscribers. I see nothing specials in the panels.
Anyway, I see that the speed is set at 100 emails per hour - should I change this setting?
best wishes,
Guy