UTR Library Designer Error

Template 5'-UTR Sequence (25NT) : AATTTAAAGGAGGTGAAATGTACAC ,     Additional Constraints for designing 5'-UTR sequence (25NT) : NNNNNNNNNNNNNNNNNNNNNNNNN

Protein Coding Sequence (at least N-term 35NT) : ATGAATGACTCGATATTCTTTTCACCCTTGAAATA

16s rRNA Sequence : ACCUCCUUA

Desired Expression Range : 1669492.26 ~ 999999999999.00 ( Desired max expression should be smaller than 1000000 )

Number of expression-level intermediates : 16