Transacvtion group config error

I had a transaction group running correctly, then I wanted to update this run-always expression item :

To this :

My group is working with a trigger on this item ‘Mois’, on value change.
Then when I saved the project to apply changes, the group stopped and is now unable to start (cf. image).
The error message is :
[color=#BF0000]Unable to start group.
Task java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask@1b49a95f rejected from java.util.concurrent.ScheduledThreadPoolExecutor@6a9d65a[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 306][/color]

Does anybody know what happened and what I sould do to fix it ?
Thanks everyone.