Overallocation in Project

Question

Hi,

I'm struggling with an overallocation issue on Project ; I hope to find help here.

My goal is to level a personal project, knowing the time I can put in each day. 

So I created my tasks, defined their duration and predecessors. Then I created a resource (myself) with a specific calendar, that I assigned to all the tasks.

Now when I try to level the project, I get an error message : 

"This overallocation cannot be resolved.  [resource] is overallocated in [project] because of the combined assignments of summary task [summary task]."

It has an effect anyway but the resource is still largely overallocated with all the tasks.

Additionnal information :

• The tasks are all auto-scheduled
• 'Level only within available slack' is unchecked
• Max. Units for the resource is 100%
• All other parameters are by default to my knowledge

What did I do wrong ?

Many thanks