Support intro
Sorry to hear you’re facing problems 
help.nextcloud.com is for home/non-enterprise users. If you’re running a business, paid support can be accessed via portal.nextcloud.com where we can ensure your business keeps running smoothly.
In order to help you as quickly as possible, before clicking Create Topic please provide as much of the below as you can. Feel free to use a pastebin service for logs, otherwise either indent short log examples with four spaces:
example
Or for longer, use three backticks above and below the code snippet:
longer
example
here
Some or all of the below information will be requested if it isn’t supplied; for fastest response please provide as much as you can 
Nextcloud version (eg, 12.0.2): 15
Operating system and version (eg, Ubuntu 17.04): Linux( I’ve installed it through Cpanel
Apache or nginx version (eg, Apache 2.4.25): 2.4
PHP version (eg, 7.1): 7.1
The issue you are facing:
- Default file are not shown, always loading.
- The “Strict-Transport-Security” HTTP header is not set to at least “15552000” seconds. For enhanced security,
- Your web server is not properly set up to resolve “/OCS-provider/”. This is most likely related to a web server configuration that was not updated to deliver this folder directly. Please compare your configuration against the shipped rewrite rules in “.htaccess” for Apache or the provided one in the documentation for Nginx at its documentation page. On Nginx, those are typically the lines starting with “location ~” that need an update.
Is this the first time you’ve seen this error? (Y/N): Yes, Newly installed
Steps to replicate it:
- No idea
- No idea
- No idea
The output of your Nextcloud log in Admin > Logging:
PASTE HERE
The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):
PASTE HERE
The output of your Apache/nginx/system log in /var/log/____:
PASTE HERE
For the above,I’m not sure how to obtain. I gone through the server manual, it describes the troubleshooting for nextcloud installed on OS like Centos… But what is my concern is how to identify and resolve the issue in installing nextcloud from Softaculous. Anyone please guide me where i can have the right user manual for web installation.