OnlyOffice Issues... ( Show it to specific groups and Language!)

Hello

I have two servers, with Ubuntu 16.04.
One server is to Nextcloud 12.
The other is to OnlyOffice 4.3.4-10.
I have successful installed and integrated both apps, but I have some issues:

1 - How can I change permantely the language? No only to doc but for entire apps? My prefered language is PT-BR.

2 - When I try to enable OnlyOffice just for some groups, I get this error:

onlyoffice can’t be enabled for groups

How can I fix it???

I’d appreciated any help.

Thanks