Hello Gaetan,
if you have data in the table AGS_CC_SIMILARIT which is not older then one week before you started the SEA analysis it should work.
If you have no errors in the logs and the table is filled you have to open a message to get it analysed further. It would be nice if you update this post later, thanks!
Daily scheduling is too short - please schedule it weekly. The job will run at the date you defined it every week.
Best regards,
Sylke
General explanation regarding similarity issues you find in SAP note 2181383.
To check the population of table AGS_CC_SIMILARIT I recommend to use the infrastructure report from SAP note 2244874 (new version of the infrastruc report that is available since SP14).. It will check the whole CCLM scenario and it should turn a red rating for the similarity check for your managed system if SEA will not find results.