Nextcloud doesn't launch without screen attached


I’m new here but use nextcloudpi since 2 years on the same raspberry pi 2.
Since one month, the raspberry starts debian, i can reach it via SSH, i can use ncp-config or others things, but Nextcloud services doesn’t appear to be started.

The only solution i have, is to plug a screen on launch, then disconnect it.
I’ve done lots of searches without result.
If someone have an idea…

Thanks in advance,