SWPM cannot process this access request

Hello! I am developing a web application that uses WordPress as a backend (Headless). That is, I consume the WordPress resources and database from the app created in Vue with Node.js through the Rest API.

User creation is simple and I have it figured out. What I’m having problems with is the login.

Apparently (and according to WordPress) SWPM is blocking the login.

More details now:

1. I send my app username and password to WordPress by Rest API using node-fetch (GET method).
2. In WordPress I have an Endpoint inside a Custom Plugin (code below).
3. This endpoint retrieves the URI parameters and sends them to wp_signon to sign in.
4. If wp_signon succeeds in logging in, it returns the user’s data. If not, it returns an error array.

This is the custom endpoint en WP:

// Register REST API endpoints
class Login_REST_API_Endpoints {

    /**
     * Register the routes for the objects of the controller.
     */
    public static function register_endpoints() {
        // endpoints will be registered here
        register_rest_route( 'wp', '/login', array(
            'methods' => 'GET',
            'callback' => array( 'Login_REST_API_Endpoints', 'login' ),
			'permission_callback' => '__return_true'
        ) );
    }

    /**
     * @param WP_REST_Request $request Full data about the request.
     * @return WP_Error|WP_REST_Request
     */
	public static function login( $request ) {


		$data = array();
		$data['user_login'] = $request["email"];
		$data['user_password'] =  $request["password"];
		$data['remember'] = true;
		$user = wp_signon( $data, false );

		if ( !is_wp_error($user) ){
			return $user;
		} else {
			return $error = json_encode(array('error' => true));
		}

	}
}
add_action( 'rest_api_init', array( 'Login_REST_API_Endpoints', 'register_endpoints' ) );

So far so good. The problem appears when I activate the SWPM plugin.

I start getting this response (the asterisks are intentional, to hide the real info):

{
	"code": "wp_die",
	"message": "<p>Warning! The Simple Membership plugin cannot process this access request to prevent you from accidentally logging out as WP admin.<\/p><p><a href=\"https:\/\/*********\/wp-admin\/profile.php\" target=\"_blank\">Click here<\/a>to see the profile with which you are logged in in this browser.<\/p><p>In this browser you have connected to the site as an administrator user. First, log out as WP admin and then you will be able to log in as a member.<\/p><p>Alternatively, you can use a different browser (where you are not logged in as an administrator) to test membership access.<\/p><p>Your frequent visitors or members will never see this message. This message is ONLY for the admin user.<\/p>",
	"data": {
		"status": 500
	},
	"additional_errors": []
}

And these are the headers when the error happens (the asterisks are intentional, to hide the real info):

Date: Sat, 11 Feb 2023 02:58:36 GMT
Server: Apache
Set-Cookie: swpm_session=52883ad4e8ad887e7***************; path=/
X-Robots-Tag: noindex
Link: <https://******/wp-json/>; rel="https://api.w.org/"
X-Content-Type-Options: nosniff
Access-Control-Expose-Headers: X-WP-Total, X-WP-TotalPages, Link
Access-Control-Allow-Headers: Authorization, X-WP-Nonce, Content-Disposition, Content-MD5, Content-Type
Expires: Wed, 11 Jan 1984 05:00:00 GMT
Cache-Control: no-cache, must-revalidate, max-age=0
Content-Length: 890
Connection: close
Content-Type: application/json; charset=UTF-8

I already tried:

• Close all sessions.
• Delete cookies and cache.
• Deactivate plugin and activate them one by one.
• Test with different browsers.
• Try with Insomnia.

And nothing works.

The only thing I have noticed is that when SWPM is disabled, the request is successful (code 200).

Could you please give me some idea of what might be going on and how I could fix it?

In use:

• SWPM 4.2.4.
• WP 6.1.1.