Is use a Docker Droplet (smallest version) and want go generate Excel Files. PHP Memory usage for this task is 34mb. Mysql Query needs 1,3 secounds.

Locally, everything is fine. Smaller “excel requests” are also fine. But when I want to generate the big Excel file, Firefox tells me “the source file could not be read …” and I only can see this Nginx error log

2019/04/20 14:20:01 [crit] 9#9: *106 open() “/var/tmp/nginx/fastcgi/0/01/0000000010” failed (13: Permission denied) while reading upstream, client: XX.XXX.156.136, serv …

Thank you & Best Regards
Simon