Sending messages with Mailboxer gem - Rails

I'm using the Mailboxer gem to send messages. Currently, I can see all sent messages, but the inbox does not have any received messages. I've tried so many things, but maybe a fresh set of eyes can spot the problem. I'm still really new to coding, so please let me know if you need more information that what I've posted below. Thanks!

Messages Controller:

 class MessagesController < ApplicationController
  before_action :authenticate_user!
 def new
   @user = User.find_by(id: params[:to].to_i) if params[:to]
   @chosen_recipient = User.find_by(id: params[:to].to_i) if params[:to]
 end

 def create
  recipient = User.find(id: params[:to].to_i) if params[:to]
  current_user.send_message(recipient, params[:message][:body], params[:message])
  flash[:success] = "Message has been sent!"
  redirect_to conversations_path
 end

private

def set_message
 @recipient = User.find(params[:receiver_id])
end

def message_params
 params.require(:message).permit(:body)
end
end

Conversations Controller:

  class ConversationsController < ApplicationController
   before_action :authenticate_user!
   before_action :get_mailbox
   before_action :get_conversation, except: [:index, :empty_trash]
   before_action :get_box, only: [:index]

 def index
  if @box.eql? "inbox"
   @conversations = @mailbox.inbox
  elsif @box.eql? "sent"
   @conversations = @mailbox.sentbox
  else
   @conversations = @mailbox.trash
  end


  @conversations = @conversations.paginate(page: params[:page], per_page: 10)
end

def show

end

private

def get_box
 if params[:box].blank? or !["inbox","sent","trash"].include?(params[:box])
  params[:box] = 'inbox'
end
 @box = params[:box]
end

def get_conversation
 @conversation ||= @mailbox.conversations.find(params[:id])
end

def get_mailbox
 @mailbox ||= current_user.mailbox
end
end

Conversations Index:

 <h1>Your Conversations</h1>

 <div class="row">
  <div class="col-sm-3">
    <ul class="nav nav-pills nav-stacked">
     <%= mailbox_section 'inbox', @box %>
     <%= mailbox_section 'sent', @box %>
     <%= mailbox_section 'trash', @box %>
    </ul>
  </div>
 <div class="col-sm-9">
  <% if @box == 'inbox' %>
   <%= current_user.mailbox.inbox %>
  <% end %>
  <% if @box == 'trash' %>
    <p><%= link_to 'Empty trash', empty_trash_conversations_path, class: 'btn btn-danger', method: :delete,
                   data: {confirm: 'Are you sure?'} %></p>
  <% end %>
  <ul class="list-group">
    <%= render partial: 'conversations/conversation', collection: @conversations %>
  </ul>

 <%= will_paginate %>
 </div>
 </div>

Conversations Partial:

  <li class="list-group-item clearfix">
   <div class="btn-group-vertical pull-right">
    <% if conversation.is_trashed?(current_user) %>
      <%= link_to 'Restore', restore_conversation_path(conversation), class: 'btn btn-xs btn-info', method: :post %>
    <% else %>
     <%= link_to 'Move to trash', conversation_path(conversation), class: 'btn btn-xs btn-danger', method: :delete,
              data: {confirm: 'Are you sure?'} %>
    <% end %>

   </div>

  <p><%= render 'conversations/participants', conversation: conversation %></p>

 <p><%= link_to conversation.last_message.body, conversation_path(conversation) %>
  <small>(<span class="text-muted"><%= conversation.last_message.created_at.strftime("%-d %B %Y, %H:%M:%S") %>     </span>)</small></p>
  </li>

New Message View:

  <h1>Start a conversation</h1>
   <%= form_tag messages_path, method: :post do %>
    <div class="form-group">
     <%= label_tag 'message[body]', 'Message' %>
     <%= text_area_tag 'message[body]', nil, cols: 3, class: 'form-control', required: true %>
    </div>
   <%= submit_tag 'Send', class: 'btn btn-primary' %>
  <% end %>