You have been dismissed from both the party and the duty.

[Mitsuka_Souji]

I was doing Palace of The Dead, and when I got to fight the boss, in the middle of battle i suddenly got black screen and then in log there was written "You have been dismissed from both the party and the duty.". I didn't get anything from instance.

What does that mean?

[Urthdigger]

It means the other party members voted to dismiss you.

[Mitsuka_Souji]

I did nothing to get dismissed, so how do I report person who abused that option?

[GrimGale]

You cannot dismiss players during combat or while rolls for items are still going on.

[frostmagemari]

I did nothing to get dismissed, so how do I report person who abused that option?

I'm going to respond as if this post was made in good faith.

Here's a better option: Stop worrying about it, and join a new PotD and get on with your life. The moment you stop trying to make sure everyone gets theirs for the slightest perceived transgression against you, the happier your gaming will become.
Are there jerks in the world? Sure; but right now, you are letting those three from the PotD group live rent free inside your head. Dust yourself off, join a new group, get on with your day and do a little more leveling through PotD.

[SuperZay]

I'm going to respond as if this post was made in good faith.

Here's a better option: Stop worrying about it, and join a new PotD and get on with your life. The moment you stop trying to make sure everyone gets theirs for the slightest perceived transgression against you, the happier your gaming will become.
Are there jerks in the world? Sure; but right now, you are letting those three from the PotD group live rent free inside your head. Dust yourself off, join a new group, get on with your day and do a little more leveling through PotD.

To add to this, a small communication when duty starts goes a long way and will prevent these conflicts. Many otherwise passive-agressive players will turn friendlier and offer advices if you say you are new. In PotD you can ask if they don't mind if you get some silver chests for upgrades (they'll usually say they don't mind even if they prefer a faster run).

[LalaRu]

I did nothing to get dismissed...

You just had back luck and the RNG gods gave you a group of unpleasant people. It happens.
As today, there too little to no tolerance to new players and in palace you may meet "speedrunners" that gets mad if you dare to visit a room looking for the blue coffers you need to level your level 1 weapon.

I'd suggest you to make runs with the friends you will surely will get over time, and maybe try to run palace even solo! it is a great school for learning how your job and skills works, more you go far in the palace more you have to be skilled, a nice challenge. Maybe you're a Necromancer in the making!!! Good luck!

[Espritduo]

The vote probably was initiated before the battle started, and the people voted during combat. Typical dick move trolls do to kick people with maximum effect.

[Erendis]

I was doing Palace of The Dead, and when I got to fight the boss, in the middle of battle i suddenly got black screen and then in log there was written "You have been dismissed from both the party and the duty.". I didn't get anything from instance.

What does that mean?

Support desk -> Contact us -> Report harrasment.

[Arngrim_Greyashe]

Unfortunately, reporting them will likely not do anything as they can simply say a difference in play styles is why they kicked you. A report won't likely do much. ☹