Cannot install additional apps

Nextcloud version: 11.0.3
Operating system and version: CentOS Linux release 7.3.1611
nginx version: 1.12.0
PHP version: 7.1.4 (php-fpm)

The issue you are facing:
Don’t know where or how to install additional apps like Calendar, Encryption plugin (like admin of course)…
I can’t see any menu or link to install additional apps.

config/config.php:
‘appstoreenabled’ => true,
‘appstoreurl’ => ‘https://api.nextcloud.com/v1’,

When logged in as Admin, in the top left menu (which shows by default ‘Files’) you should see a ‘+’ sign which will bring you to the apps menu.

Yes and then what?

You should see a complete list of categories, but seems you don’t. Does your NC have internet access to be able to contact apps.nextcloud.com ? Check also your nextcloud.log for any entries which might show any issues.

Thank you for your input Stephan!
I checked the log and in my case, the problem was that there was a bad rootcerts.crt inside the files_external folder (in the nextcloud /data directory). Removing it fixed the problem, and all apps appeared.

@hibner: The two lines you cite do not seem to be necessary… they have no impact for me, whether they exist or not.

For other stumbling on issues with api.nextcloud.com
The api.nextcloud.com is appearantly discontinued and only redirects the URL, the ssl cert doesn’t have api.nextcloud.com in Subj. or SAN. ==> fails to redirect.