Nginx customization


I use on my server:
linuxserver / piwigo
linuxserver / swag

I did not touch the initial configuration and it works. Only the day before yesterday, I wanted to download a finier on PIWIGO of 300 MB or more and impossible I found this error in the logs of the swag container and in that of the piwigo container:

upstream prematurely closed connection while reading upstream, client:, server: photos. *, request: “GET /action.php?id=5496&part=e&download HTTP / 2.0”, upstream: " 80 / action.php? Id = 5496 & part = e & download "

While researching, I saw that it was necessary to play on the values of:

Being a new one in the Nginx configuration I am not out of it. can you help me find the correct configuration please?