After password change 504 on user login and console user password wrong

Good evening,

My status so far:
I added the timeout option to the nginx config as mentioned here. That got me back in for the user portal.

Still I can’t use sudo with my user and I thought why not try to ‘sync’ the password with what yunohost knows:
when I run the passwd command (be it with root or myuser)
i get the following same answer :

(current) LDAP Password: 
passwd: Authentication token manipulation error
passwd: password unchanged

and with root :

LDAP administrator password: 
passwd: Authentication token manipulation error
passwd: password unchanged

The error is normal? In both case?

How is the login system checking the security?