user.update rollback error in model method - ruby-on-rails

Question

As everything working as expected, i'm trying to save the new values in the database but i'm getting a rollback error on update
my model.rb
class User < ApplicationRecord
before_update :update_password
def self.update_password(username, new_password, new_password_conf, old_password)
user = find_by_username(username)
if new_password == new_password_conf && BCrypt::Engine.hash_secret(old_password, user.salt) == user.encrypted_password
new_salt = BCrypt::Engine.generate_salt
new_pass = BCrypt::Engine.hash_secret(new_password, new_salt)
user.update(encrypted_password: new_pass, salt: new_salt)
else
puts "Something went Wrong"
end
end
end
my users_controller.rb
def change_password
user = User.update_password( User.find(session[:user_id]).username,params[:password],params[:password_confirmation],params[:old_password])
end
my html.erb
<%= form_for(:user, :url => {:controller => 'users', :action => 'change_password'}) do |f| %>
<center><p> Παλιός Κωδικός Πρόσβασης</br> <%= f.password_field :old_password, placeholder: "Παλιός Κωδικός Πρόσβασης", name: "old_password"%> </p></center>
<center><p> Νέος Κωδικός Πρόσβασης</br> <%= f.password_field :password, placeholder: "Νέος Κωδικός Πρόσβασης", name: "password"%></p></center>
<center><p> Επιβεβαίωση Νέου Κ.Πρόσβασης</br> <%= f.password_field :password_confirmation, placeholder: "Επιβεβαίωση Νέου Κ.Πρόσβασης", name: "password_confirmation" %></p></center>
<center><%= f.submit "Αποθήκευση", class: 'log_in_button' %><center>
<% end %>
Console output
Started POST "/users/change_password" for 127.0.0.1 at 2020-08-10 01:13:18 +0300
Processing by UsersController#change_password as HTML
Parameters: {"authenticity_token"=>"ORVdeLRZYMjP7XIMqligykYH7YqnjzprTpQnCl3G9XPj36hgEEcC+C/Y1F6Tp3QTOVrheaYD/SZM0BX+i3YERQ==", "old_password"=>"[FILTERED]", "password"=>"[FILTERED]", "password_confirmation"=>"[FILTERED]", "commit"=>"Αποθήκευση"}
User Load (0.4ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT $2 [["id", 1], ["LIMIT", 1]]
↳ app/controllers/users_controller.rb:76:in `change_password'
User Load (0.4ms) SELECT "users".* FROM "users" WHERE "users"."username" = $1 LIMIT $2 [["username", "mauras"], ["LIMIT", 1]]
↳ app/models/user.rb:36:in `update_password'
(0.2ms) BEGIN
↳ app/models/user.rb:41:in `update_password'
User Exists? (0.4ms) SELECT 1 AS one FROM "users" WHERE "users"."username" = $1 AND "users"."id" != $2 LIMIT $3 [["username", "mauras"], ["id", 1], ["LIMIT", 1]]
↳ app/models/user.rb:41:in `update_password'
User Exists? (0.4ms) SELECT 1 AS one FROM "users" WHERE "users"."email" = $1 AND "users"."id" != $2 LIMIT $3 [["email", "asdas#adasd.com"], ["id", 1], ["LIMIT", 1]]
↳ app/models/user.rb:41:in `update_password'
(0.3ms) ROLLBACK
↳ app/models/user.rb:41:in `update_password'
Rendering users/change_password.html.erb within layouts/application
Rendered users/change_password.html.erb within layouts/application (Duration: 0.8ms | Allocations: 365)
[Webpacker] Everything's up-to-date. Nothing to do
Completed 200 OK in 608ms (Views: 6.3ms | ActiveRecord: 2.1ms | Allocations: 10770)
also try user.save still nothing,