function array_to_string(text[]) does not exist

Hello

When I run :
SELECT array_to_string(array_agg(CONCAT(CAST (ltrv1.val_min AS CHAR),
'-', CAST(ltrv1.val_max AS CHAR), ' ', ltrv1.comentarii)))
FROM lab_tests_reference_values ltrv1
GROUP BY ltrv1.val_min, ltrv1.val_max, ltrv1.comentarii;

I get the error:
ERROR: function array_to_string(text[]) does not exist
LINE 1: SELECT array_to_string(array_agg(CONCAT(CAST (ltrv1.val_min ...
^
HINT: No function matches the given name and argument types. You might
need to add explicit type casts.

I tryed to cast but it's still not working.

Thanku you.