So I realize I have a learning curve ahead...

I am trying different ways of resolving issues regarding over allocated resources within a masterplan and right now I have a scenario where I have a couple of tasks not resolving overallocation when leveling

Two tasks, each 0,5 days with the constraint must-start-on 2017-02-14 and a priority set to 1000 since they both are booked meetings with client. They are allocated on the same resource and after leveling they still show up as conflicts.
I do have other tasks allocated on that same resource but none of the other tasks have any constraints.

My lack of knowledge I think begins with finding the right view to establish what really creates the conflict since I do not get any warnings about unresolvable conflicts.

Where am I going wrong in this and what steps should I do to establish a solution to this?

Cheers!