Nextcloud iOS App rewrite to /nextcloud


we have installed nextcloud 16 on ubuntu 18.04 with nginx and use the reverse proxy functionality.
Nextcloud is installed in the subfolder /var/www/nextcloud.

I have create a redirect in the /etc/nginx/conf.d/cloud.domain.tdl.conf to the /nextcloud folder.

location = / {
rewrite ^ /nextcloud;

For the windows browsers firefox/chrome etc. the redirect works perfect.

In the iOS App on iPhone/iPad the redirect does not work. Is this a error in my configuration or by design?
Is it possible to configure the ios app to check the domain https://nextcloud.domian.tdc and https://nextcloud.domain.tdc/nextcloud?

Best regards,