External site as default app

Hi, Iā€™m trying to include and external forum into NextCloud. Thereā€™s no easy way to integrate users and login, but I can leave with it. So far Iā€™ve been able to add the external site link in the top bar, but I would like to make the forum the default app the user will be leaded after login.

I think I should do that by editing the config.php and maybe adding the defaultapp option, but I donā€™t know how to specify the external site as default app.

BTW Iā€™ve not been able to change the defaultapp even with other installed app, for instance Iā€™ve tried:

ā€˜defaultappā€™=>ā€˜dashboardā€™, (the dashboard app is active)

or

ā€˜defaultappā€™=>ā€˜external/2ā€™, (the link as it appears when I click on the external site icon)

but they donā€™t work.

Actually Iā€™ve never been able to change the defaultapp behaviour.

Iā€™m using the 12 server.

Any help?