Onlyoffice dont work with nextcloud

I have installed Seafile and Nextcloud and Onlyoffice on my Yunohost server.
In nextcloud I have installed the Onlyoffice Connector
There is no connection with the server
https://mydomain/nextcloud does not work
https://mydomain/onlyoffice does not work

following Error message appears

Fehler beim Anschließen (Client error: GET https://mydomain/onlyoffice/healthcheck resulted in a 404 Not Found response: Private Seafile

Seem to be a problem with also installed seafile

Do I have to install the Onlyoffice APP in Nextcloud anyway ?

hello,
your applications must be installed on differents sub-domains
example:
https://nextcloud.mydomain.com/ for nextcloud
https://onlyoffice.mydomain.com/ for onlyoffice