Adding an user to a group causes unable to find user, but the user exists. I have 32 users and the error only occurs with 3 specific users. the error continues after recreating those users The username that can not be added to any group are: eventos, mantenimiento, contabilidadd-i System version …

You probably have some machine accounts with the same of the users. You need to inspect the Samba container status: net ads search -P objectClass=Computer If you find something strange, you need to access the container and remove the machine accounts using samba-tool. To have a shell inside the …