NCP Account not Available


I am a windows user with poor knowledge about Linux and working with the shell.
A few month ago I installed my first Nextcloud on a Raspberry Pi (from own your bits). Worked all well until 2 weeks it suddenly has been in maintenance mode. Without SSH activated I had to plug it off to take it from a server room to my monitor. Then I plugged the SSD out.

Now I cant even log in as NCP User (admin).
I have no backup…
NCP v 1.36.3 on a RaspberryPi 4 Model B
with 32GB SD card (for OS) and 1TB SSD (for data, not plugged in):

If I try to log in it says:

Last Login…
fatal: unable to access…
The git clone command failed: No connectivity…
grep: /var/run/.ncp-latest-version: No such file or directory


NCP is up to date v 1.36.3
No directory, logging in with home=/
This account is currently not available

Debian GNU /Linux10 Nextcloudpi tty1

Coud somebody please give me a few hints / links what to try/what to check?
I guess I shoud turn it off (how?) to take the sd card out, into a sd card reader (windows pc) to repair something so that I can log in again…

Thanks a lot in advance