Hi,
Since two days I have a 403 error when I want to go to administration interface. The first time I suspected a problem with uninstall Openkdim (mistake on the code).
Yesterday, new installation with FreshRss/Kanbord/Nextcloud/Dokuwiki. No modifications on the base of nginx.
The prompt “nginx -t” … Succesfull.
I can use apps which are installated. But going to the administration interface. Not possible. It is really annoying, really.
Thanks for help me ! 
Hey, Did you tried to access the same page from some other pc or laptop? If the problem persists then it may be beacuse the webiste owner has restricted you from access that page. Well there’s a simple soln. to it…Install gom vpn extension from here.it will let you bypass this restriction in seconds.
A 403 Forbidden error is a particular type of error that occurs when trying to access a URL. If you’re seeing a 403 Forbidden error, there are two possible causes. It could be due to a removal of file permission, or restriction of access based on the IP address of the user. If you have any kind of problem with your windows then you may visit here Windows Technical Support to solve your windows related errors.