How to fix nextcloud error "This content failed to load."?

Question

Nginx

Installed Nextcloud after installation, the error "This content failed to load." and the page keeps reloading.
Nextcloud 14
Nginx
Debian 9
Mariadb
nginx.conf

user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
        worker_connections 768;
        # multi_accept on;
}

http {

        ##
        # Basic Settings
        ##

        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        keepalive_timeout 120;
        types_hash_max_size 2048;
        # server_tokens off;

        # server_names_hash_bucket_size 64;
        # server_name_in_redirect off;

        include /etc/nginx/mime.types;
        default_type application/octet-stream;

        ##
        # SSL Settings
        ##

        ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
        ssl_prefer_server_ciphers on;

        ##
        # Logging Settings
        ##

        access_log /var/log/nginx/access.log;
        error_log /var/log/nginx/error.log;

        ##
        # Gzip Settings
        ##

        gzip on;
        gzip_disable "msie6";

        # gzip_vary on;
        # gzip_proxied any;
        # gzip_comp_level 6;
        # gzip_buffers 16 8k;
        # gzip_http_version 1.1;
        # gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

        ##

        ##
        # Virtual Host Configs
        ##

        include /etc/nginx/conf.d/*.conf;
        include /etc/nginx/sites-enabled/*;
}


#mail {
#       # See sample authentication script at:
#       # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
#       # auth_http localhost/auth.php;
#       # pop3_capabilities "TOP" "USER";
#       # imap_capabilities "IMAP4rev1" "UIDPLUS";
#
#       server {
#               listen     localhost:110;
#               protocol   pop3;
#               proxy      on;
#       }
#
#       server {
#               listen     localhost:143;
#               protocol   imap;
#               proxy      on;
#       }
#}

nextcloud:

upstream php-handler {
    server unix:/var/run/php/php7.0-fpm.sock;
}

server {
    listen 80;
    server_name 192.168.2.100 cloud.site;
    root /var/www/nextcloud/;

    access_log /var/log/nginx/cloud.help-me-24.com.log;
    error_log /var/log/nginx/cloud.help-me-24.com-error.log;

    add_header X-Content-Type-Options nosniff;
    add_header X-XSS-Protection "1; mode=block";
    add_header X-Robots-Tag none;
    add_header X-Download-Options noopen;
    add_header X-Permitted-Cross-Domain-Policies none;

    location = /robots.txt {
        allow all;
        log_not_found off;
        access_log off;
    }

    rewrite ^/.well-known/host-meta /public.php?service=host-meta last;
    rewrite ^/.well-known/host-meta.json /public.php?service=host-meta-json;

    location = /.well-known/carddav {
      return 301 $scheme://$host/remote.php/dav;
    }
    location = /.well-known/caldav {
      return 301 $scheme://$host/remote.php/dav;
    }

    client_max_body_size 512M;
    fastcgi_buffers 64 4K;

    gzip off;

    location / {
        rewrite ^ /index.php$uri;
    }

    location ~ ^/(?:build|tests|config|lib|3rdparty|templates|data)/ {
        deny all;
    }
    location ~ ^/(?:\.|autotest|occ|issue|indie|db_|console) {
        deny all;
    }

    location ~ ^/(?:index|remote|public|cron|core/ajax/update|status|ocs/v[12]|updater/.+|ocs-provider/.+|core/templates/40[34])\.php(?:$|/) {
        fastcgi_split_path_info ^(.+\.php)(/.*)$;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_param PATH_INFO $fastcgi_path_info;
        fastcgi_param modHeadersAvailable true;
        fastcgi_param front_controller_active true;
        fastcgi_param PHP_VALUE "
                opcache.enable=1
                opcache.enable_cli=1
                opcache.interned_strings_buffer=8
                opcache.max_accelerated_files=10000
                opcache.memory_consumption=128
                opcache.save_comments=1
                opcache.revalidate_freq=1";
        fastcgi_pass php-handler;
        fastcgi_intercept_errors on;
        fastcgi_read_timeout 300;
    }

    location ~ ^/(?:updater|ocs-provider)(?:$|/) {
        try_files $uri/ =404;
        index index.php;
    }

    location ~* \.(?:css|js|woff|svg|gif)$ {
        try_files $uri /index.php$uri$is_args$args;
        access_log off;
    }

    location ~* \.(?:png|html|ttf|ico|jpg|jpeg)$ {
        try_files $uri /index.php$uri$is_args$args;
        access_log off;
    }

}

Answer 1

in logs

2018/09/09 00:30:05 [error] 2882#2882: *6 FastCGI sent in stderr: "PHP message: PHP Warning: Zend OPcache can't be temporary enabled (it may be only disabled till the end of request ) in Unknown on line 0" while reading response header $