This is not a WordPress issue. Your domain’s name servers are not properly set up. Please work with your domain registrar to correct this.
[sdstern@cumberland ~]$ whois silkeciasp.com.br
% Copyright (c) Nic.br
% The use of the data below is only permitted as described in
% full by the terms of use at https://registro.br/termo/en.html ,
% being prohibited its distribution, commercialization or
% reproduction, in particular, to use it for advertising or
% any similar purpose.
% 2016-10-25 10:15:20 (BRST -02:00)
domain: silkeciasp.com.br
owner: G3 - ARTES GRáFICAS LTDA-ME
ownerid: 059.487.264/0001-64
responsible: SILVIO GERMINHASI
country: BR
owner-c: RSG220
admin-c: RSG220
tech-c: RSG220
billing-c: RSG220
nserver: ns1.silkeciasp.com.br 66.7.199.236
nsstat: 20161025 FAIL
nslastaa: 20160928
nserver: ns2.silkeciasp.com.br 66.7.199.237
nsstat: 20161025 FAIL
nslastaa: 20160928
saci: yes
created: 20140423 #12818982
expires: 20170423
changed: 20160908
status: published
nic-hdl-br: RSG220
person: rubens silvio germinhasi
e-mail: [email protected]
created: 20060420
changed: 20140417
% Security and mail abuse issues should also be addressed to
% cert.br, https://www.cert.br/ , respectivelly to [email protected]
% and [email protected]
%
% whois.registro.br accepts only direct match queries. Types
% of queries are: domain (.br), registrant (tax ID), ticket,
% provider, contact handle (ID), CIDR block, IP and ASN.
[sdstern@cumberland ~]$ nslookup silkeciasp.com.br
;; Got SERVFAIL reply from 8.8.4.4, trying next server
Server: 8.8.4.4
Address: 8.8.4.4#53
** server can't find silkeciasp.com.br: NXDOMAIN