Hello, a little feedback to explain how i had resolve this problem.
In my case, all the jobs of a server/agent in submitted after rebooting the server.
After a lot of checking, I noticed that in the platform "automate schedule" in the menu "agents" sub menu "agents" I had the agent which was in duplicate (one created at the date of the server restart).
As a result, one of them was inactive and unlicensed.
Solution : right click and do a "replace" with the agent having the same name.
If this does not solve your problem, go to the "agents" menu under "Job queues" and check the status of your agent.
Do not hesitate to right click and select "release job queue".
Et voila !