For further reference: DNSViz and UnboundTest also don't see anything wrong with the DNS:
https://dnsviz.net/d/www.itanhaem.sp.gov.br/Y9qy6A/dnssec/
https://unboundtest.com/m/A/www.itanhaem.sp.gov.br/LZ56XTTP
https://unboundtest.com/m/AAAA/www.itanhaem.sp.gov.br/PPHLIPU5