You have not connected the ‘Set Dyanamicmaterial Cursor’ node to anything. You should connect the Exit pin of ‘Create Dynamic Material Instance’ node to the Entry pin of that node. Then connect the Exit pin of ‘Set Dyanamicmaterial Cursor’ to branch.
BUT you are doing something terribly wrong here. You are creating a dynamic material instance in every tick. Thats not how you should do it. The creation of Dyanmic material instance should be done only once. SO move it to Construct event.
So everything before the ‘Branch’ node should be moved to Construct.