Fairphone 6 stay in FastBoot Mode and i can't turn it off after succefull install e.foundation/installer/

Hello,
I try to install e/os on Fairphone 6 Andorid version with the e/os/ installer
On the chrome browser i have succesfull installation message. i see the murena logo a short time and then i see the Fast Boot Mode.
Now i’m block in Fast Boot mode, i try to turn off the Fairphone 6, by pressing the power botton but it make a loop > logo android > Start FastBoot Mode.

I try this : fastboot flashing unlock
FAILED (remote: ’ Device already : unlocked!')
fastboot: error: Command failed

Can somebody help me to get out of this situation ?
Thank’s

------- Now i got this message <!> The boot loader is un unlocked and software intergry cannot be garanteed… and I see Fairphone logo android visit Understand warning about operating system safety - Android Help, i’m in a new loop.

Regain your privacy! Adopt /e/OS the deGoogled mobile OS and online servicesphone

Perhaps try the advice here FP6 stuck on fastboot mode - in need of help - #2 by aibd

Thank’s aibd, for your help, i’m back on Android.
I was very close, even if the installer says that i intalled e/os i have just notice this error message on /e.foundation/installer/ :
Error on step: flashing
this is not the current step installation-complete is not equals to flashing

Maybe it could help to improve the /e.foundation/installer/ or maybe this error message in about a wrong seeting on my side ?