function cannot be referenced -- it's a deleted function

i am working on a C++ project for my uni but i have some troubles. I am trying to read the nodes for Board class from a .txt file, but there is a king of error with overloading operator = when i am trying to put these coordinates into my array. There arenter image description heree some photos the nodes .txt

the problem function

My array: array ( where NODES_COUNT it's a constat initialized with 54)

And that's my StructureSlot class: header

CPP

Somebody may help me why i can't populate that array nodes?