I just formulated an answer but Research Gate seems to swallow my writings and scrambles all letters.
So I try again:
First: why do you ask ME this question?
I'm actually not so familiar with Abaqus, since I didn't use it for several years.
2.: I have no idea what you did before you got this nmessage.
But obviously you use a node set for anything and abaqus does not know it. Could it be that you gave the node sets longer names and they are truncated by abaqus ?