[Snapshot Pro] Snapshot backup is not working 504 Gateway Time-out,

Snapshot backup is not working because of Nginx it get me 504 Gateway Time-out, Nginx, after having

but my settings were validated by the snapshot testing environement

128M (Default)
max_execution_time
300 (Default)
max_input_time
300 (Default)
post_max_size
8M (Default)
upload_max_filesize
2M (Default)
opcache.enable
on (Default)
disable_functions
opcache_get_status (Default)

Its on a plesk, apache Php 7.1, with Nginx.
It’s stay stuck at 86% for a long time and then block

I see in console a lot of Ajax calls, like the last one
{“Données de formulaire”:{“action”:”snapshot_backup_ajax”,”snapshot-proc-action”:”file”,”snapshot-action”:”update”,”snapshot-item”:”1574950289″,”snapshot-data-item”:”1574958810″,”snapshot-file-data-key”:”media”,”security”:”2bd1bb4f43″}}

and then 504
{“Données de formulaire”:{“action”:”snapshot_backup_ajax”,”snapshot-proc-action”:”file”,”snapshot-action”:”update”,”snapshot-item”:”1574950289″,”snapshot-data-item”:”1574958810″,”snapshot-file-data-key”:”plugins”,”security”:”2bd1bb4f43″}}