Seems you had a little trouble with typing... you need help on the mandalore mission? You have a defiler there, but you can't seem to start the piracy mission. Turns out, the ONLY unit you can send there is the defiler. If you try to send other units, the tutorial will not allow you to.
The misson says you need Tyber Zann to help you. However, you do not need to send him there. Try initiating the mission with only a Defiler in orbit. Done correctly, Zann should automatically participate in the mission.
If it still doesn't start, I don't know what else you can do....