DNS Registro.br transffer - error

[hardbrasil]

Hello fellas, i am trying to transfer some domains (dns) on my registrar in Brasil
https://registro.br

i have configured my server like others (ded.) we have 4 servers in 3 dif. companies
what happen is, sometimes the dns change has success and others i got time out.

i presume that sometimes my DNS (host) stop to propagate than i my Registrar don't recognize them,

i really dont know what to do to. The 1and1 support is not so good, they dont help...