Unable to insert image from iOS app

I am running WordPress 4.7.2 by creating CentOS7 in the Docker container in CentOS7.
The http server is Apache/2.4.6.PHP 5.4.16.

When I insert an image from iOS's WordPress app, the error screen looks like the one below.

When I insert an image from iOS's PressSync app, the error screen appears below.

Posts that do not involve image insertion can be done without any problems.

Even in php configuration
memory_limit=1000M
post_max_size=100M
upload_max_filesize=100M
max_input_time=60
and quite high.

An HTTP error occurred when I uploaded the iPhone photo directly to the media even from the browser.
Shrink and upload will succeed.

If you know how to solve this problem, please let me know.

== (Self-resolved) ==
The front of the Docker container used by wordpress is proxy_passing with nginx.

in that nginx configuration client_max_body_size 100M;
was configured.