Can't Grant Users Update permission
The user that has access problems is the member of many win groups,
even if he's a member of db_owner he has limited access if someone revoke/deny some permissions to him or to his group.

To find out restrictions you should use this query:

execute as user = 'NETONE\İbrahim.tackin';   
select user_name(grantee_principal_id) as user_,
       permission_name,
       object_name(major_id) as obj_name,
       class_desc,
       state
from sys.database_permissions p
     join sys.user_token t
        on p.grantee_principal_id = t.principal_id
where state in ('D', 'R');
revert;


Here I limit the result to those roles/win groups of which problem user is a member of.

So your user has 3 DENY of UPDATE on all database:

NETONE\sql-ict-ad-rms UPDATE NULL DATABASE D
NETONE\SQLDDL UPDATE NULL DATABASE D
NETONE\SQLQRY UPDATE NULL DATABASE D


Your user will be unable to perform any UPDATE until you revoke these denies:

revoke update to [NETONE\İbrahim.tackin],[NETONE\SQLDDL],[NETONE\SQLQRY]


If you don't deny by error and the members of these 3 groups should not be able to update, you should exclude all your users that should be able to update from all these 3 groups.

Note you have same 3 deny to make a delete.



The permissions of any user is given by the "sum" of all the permissions that were granted/denied to him and his groups/roles.

Until your user is a member of win group that has update denied he will not be able to update. To make him  be able to update you should exclude him from grous with deny or revoke deny from these groups.