in case of the result is more than the maximum size, how could someone process?

I'm trying to concatenate, two values that are the same field but in different rows, with a query like this "SELECT BB.EMPLID, LISTAGG(AA.DESCR,', ') WITHIN GROUP (ORDER BY AA.DESCR) AS DESCR_CICLO_CRSADO FROM PS_TERM_TBL AA".

when trying to compile this it throws me an error that goes like "result of string concatenation is too long 

Cause: String concatenation result is more than the maximum size.

Action: Make sure that the result is less than the maximum size."

If anyone can tell me another way to do it or how to put this query together so I don't get this error message.