Test the equality of two lists with == does not work for me

I work with large lists (more than 500 items). call them liste1 and list2. I edited liste1 and list2 so that they do not contain repeated elements. I've tried the commands

list1 == list2

and

Sort[list1] == Sort[list2]

to check if the lists are equal but instead of getting an output of True or False. I receive the returned entry expression not evaluated.

For example if I defined

list1: = {1,2,3}
list2: = {2,3,4}

then

list1 == list2

will come back

{1,2,3} == {2,3,4}

What am I doing wrong? How can I solve this?

I would be surprised if this evaluation only worked for sufficiently small lists.