PHP Artisan Tinker ERROR relation [pivot_table] does not exist

I have a 'clients' table and a 'messages' table'. These two have a ManyToMany relationship, so I created a pivot table called 'client_message'. The 'clients' and 'messages' tables were already existing in our Postgres database so I didn't have to create them using a migration. I also created the 'client_message' table directly in the database without using a migration.

The 'clients' table has a custom id called 'clients_id' so I had to set the primaryKey:

protected $primaryKey = 'clients_id';

Thsi is my 'clients' table structure:

CREATE TABLE IF NOT EXISTS spot.clients
(
    clients_id integer NOT NULL GENERATED ALWAYS AS IDENTITY ( INCREMENT 1 START 1 MINVALUE 1 MAXVALUE 2147483647 CACHE 1 ),
    message_id integer NOT NULL,
    mac character varying(17) COLLATE pg_catalog."default" NOT NULL,
    ave_rssi numeric(5,2),
    CONSTRAINT clients_pkey1 PRIMARY KEY (clients_id)
)

This is my 'messages' table structure:

CREATE TABLE IF NOT EXISTS spot.messages
(
    message_id integer NOT NULL GENERATED ALWAYS AS IDENTITY ( INCREMENT 1 START 1 MINVALUE 1 MAXVALUE 2147483647 CACHE 1 ),
    "timestamp" timestamp without time zone,
    ap_mac character varying(30) COLLATE pg_catalog."default" NOT NULL,
    ap_id integer NOT NULL,
    ave_rssi numeric(5,2),
    airtime smallint,
    band smallint,
    number_of_clients integer,
    CONSTRAINT messages_pkey1 PRIMARY KEY (message_id)
)

This is my pivot table (client_message) structure:

CREATE TABLE IF NOT EXISTS spot.client_message
(
    id integer NOT NULL DEFAULT nextval('spot.client_message_id_seq'::regclass),
    clients_id integer NOT NULL,
    message_id integer NOT NULL,
    created_at timestamp without time zone,
    updated_at timestamp without time zone,
    CONSTRAINT client_message_pkey PRIMARY KEY (clients_id, message_id)
)

When I go use PHP Artisan tinker, I can get an individual client record:

>>> $client = App\Client::find(232842935);
=> App\Client {#4792
     clients_id: 232842935,
     message_id: 10420248,
     mac: "F6:E6:0D:F3:1F:20",
     ave_rssi: "128.00",
   }

But when I attempt to get the message related to the client, I get an error:

>>> $client->message
=> null
>>> $client->messages
Illuminate\Database\QueryException with message 'SQLSTATE[42P01]: Undefined table: 7 ERROR:  relation "client_message" does not exist
LINE 1: ...ot_message_message_id" from "messages" inner join "client_me...
                                                             ^ (SQL: select "messages".*, "client_message"."client_clients_id" as "pivot_client_clients_id", "client_message"."message_message_id" as "pivot_message_message_id" from "messages" inner join "client_message" on "messages"."message_id" = "client_message"."message_message_id" where "client_message"."client_clients_id" = 232842935)'

Apparently, the pivot table is not visible to tinker and I don't know why.

Here is the 'Client' model class:

<?php

namespace App;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Client extends Model
{
    use HasFactory;

    protected $primaryKey = 'clients_id';

    protected $table = 'clients';
    /**
     * Client shows up in many messages
     *
     * @return mixed
     */
    public function messages()
    {
        return $this->belongsToMany(Message::class);
    }
}

And here is the 'Message' model class:

<?php

namespace App;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Message extends Model
{
    use HasFactory;

    protected $primaryKey = 'message_id';

    /**
     * Message has many clients - Many to Many
     *
     * @return mixed
     */
    public function clients()
    {
        return $this->belongsToMany(Client::class);
    }

    /**
     *
     *
     * @return mixed
     */
    public function controllerAp()
    {
        return $this->belongsTo(ControllerAp::class);
    }
}

Why can't I see the messages with Tinker?