Solved for me! Checked 3 times.
Prestashop v 1.7.5
Config
nginx + PHP -FPM 7.1/ICU 63.1
Php extra parameters.
allow_url_fopen = true;
upload_max_filesize = 128M;
post_max_size = 128M;
memory_limit = 1024M;
max_execution_time = 600;
max_input_time = 600;
max_input_vars = 600;
register_globals = Off
magic_quotes_gpc = Off
allow_url_include = Off
safe_mode = Off
safe_mode_gid = Off
default_socket_timeout = 240
mysql.connect_timeout = 240
----------------------------------
nginx extra parameters
try_files $uri =404;
include /etc/nginx/fastcgi_params;
fastcgi_pass unix:/var/lib/php7.0-fpm/web8.sock(check for your parameter);
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
fastcgi_intercept_errors on;
fastcgi_split_path_info ^(.+.php)(/.*)$;
fastcgi_read_timeout 300s;
fastcgi_send_timeout 300s;
fastcgi_buffer_size 128k;
fastcgi_buffers 256 16k;
fastcgi_max_temp_file_size 0;
fastcgi_busy_buffers_size 256k;
fastcgi_temp_file_write_size 256k;
-------------------------------------------
Change browser to opera.!!!!!!!!!!!!!!!!!!