Hi Everybody,
Now the sending is working fine at my side.
I’m going to explain you that I do to solve the problem.
Mainly, 2 things seems to be necessary to restart the automatic send of Mailpoet.
1 – I’ve configure a cron task at my provider. (So, I solved also my automatic backup with UpDraftPlus which didn’t run)
2 – After, I have created a new newsletter but not from a duplicate.
After that, my automatic send has worked fine. I hope it will help you !