Rails not displaying error messages when submitting a form - ruby-on-rails

Question

I'm new to rails so I have a Signup controller that looks as follows:
class SignupController < ApplicationController
def new
#user = User.new
end
def create
#user = User.new(user_params)
if #user.save
redirect_to root_path, notice: "You are logged in as #{#user[:username]}"
else
puts #user.errors.full_messages
render :new
end
end
private
def user_params
puts params
params.require(:user).permit(:email, :password, :password_confirmation, :username)
end
end
So I'm trying to create a new user when I submit the form and my routes.rb file contains the following:
Rails.application.routes.draw do
root to: "home#index"
get '/about-us', to: "about#index", as: :about
# signing up
get 'sign_up', to: "signup#new"
post 'sign_up', to: "signup#create"
end
My app/views/signup/new.html.erb file has the following code in it:
<h1>Sign Up</h1>
<%= form_with model: #user, url: sign_up_path do |form| %>
<%= #user.errors.full_messages.inspect %>
<% if #user.errors.any? %>
<div class="alert alert-danger">
<% #user.errors.full_messages.each do |message| %>
<div><%= message %></div>
<% end %>
</div>
<% end %>
<div class="mb-3">
<%= form.label :email, class: "form-label"%>
<%= form.text_field :email, placeholder: "email#gmail.com", class: "form-control"%>
</div>
<div class="mb-3">
<%= form.label :username, class: "form-label"%>
<%= form.text_field :username, placeholder: "username", class: "form-control"%>
</div>
<div class="mb-3">
<%= form.label :password, class: "form-label"%>
<%= form.password_field :password, placeholder: "password", class: "form-control"%>
<div class="mb-3">
<%= form.label :password_confirmation, class: "form-label"%>
<%= form.password_field :password_confirmation, placeholder: "password", class: "form-control"%>
</div>
<div class="mb-3">
<%= form.submit "Sign Up", class: 'btn btn-primary'%>
</div>
<% end %>
But it seems like I'm getting the error messages in the console but they can't be rendered in the template when i submit the form with errors. Here is the errors i'm getting:
Password can't be blank
Email can't be blank
Email invalid email address
Username can't be blank
What maybe possibly the problem with my code here.

Answer 1

In your form, try this instead
<% if #user.errors.any? %>
<div class="alert alert-danger">
<% #user.errors.each do |error| %>
<div><%= error.full_message %></div>
<% end %>
</div>
<% end %>

Answer 2

I was using rails version 7.* so I manage to solve this error by changing the create method in the SignupController to :
def create
#user = User.new(user_params)
if #user.save
redirect_to root_path, notice: "You are logged in as #{#user[:username]}"
else
puts #user.errors.full_messages
render :new, status: :unprocessable_entity, content_type: "text/html"
end
end
This is according to the suggestions i got from Alex in the comments together with the discussion that i found here.