Error Device Sync

Hello,
I’m facing a probleme on my production env app…
I have synchronization probleme between Atlas and Device Sync. Also when i’m try to update/insert new data (to obtain logs) I see in Realm log a this:

[
  "Upload message contained 1 changeset(s)",
  "Integrating upload required conflict resolution to be performed on 0 of the changesets",
  "Latest server version is now 12",
  "Number of upload attempts was 1"
]

I’ve checked my datas and schemas before trying to Sync and everything is alright.
Someone have an idea ?? :pray: