I have had problems importing "long" (>20) CSV users lists since I started using Chamilo back in 1.10.*. It's a timeout problem(1), but although I have increased time parameters in the php.ini file it seems like I haven't found the right file/parameter yet. I am using an external email service so it takes a little extra for all of them to go out, adding time to the whole process. If the list is short enough (lets say 10 users), everything goes alright. I'll appreciate any ideas about what parameter to increase.
(1) From the server error log:
2017/03/28 17:16:29 [error] 3569#3569: *1952 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 192.168.1.2, server: ***, request: "POST /main/admin/user_import.php HTTP/1.1", upstream: "https://192.168.1.8:8443/main/admin/user_import.php", host: "***", referrer: "https://***/main/admin/user_import.php"