Experimente esta configuração:
<Directory /usr/share/phpMyAdmin/>
AddDefaultCharset UTF-8
<IfModule mod_authz_core.c>
# Apache 2.4
<RequireAny>
Require ip 127.0.0.1
Require ip ::1
Require ip 27.34.248.3
</RequireAny>
</IfModule>
<IfModule !mod_authz_core.c>
# Apache 2.2
Order Deny,Allow
Deny from All
Allow from 127.0.0.1
Allow from ::1
Allow from 27.34.248.3
</IfModule>
</Directory>
Reinicie o serviço Apache:
systemctl restart httpd