CakePHP 3 doesn't submit the forgeign key fields value - cakephp

Question

I have the following 2 tables, and the default classes generated from
bin/cake bake all clients
bin/cake bake all clients_address
When I try and add an address, setting the "client_id" to 1, I get the following error.
Error: SQLSTATE[HY000]: General error: 1364 Field 'client_id' doesn't have a default value
If you are using SQL keywords as table column names, you can enable identifier quoting for your database connection in config/app.php.
SQL Query:
INSERT INTO clients_address (address_line_1, address_line_2, address_line_3, town, county, postcode, email, tel, contact_name, default_address) VALUES (:c0, :c1, :c2, :c3, :c4, :c5, :c6, :c7, :c8, :c9)
Is there some extra code needed to get the client_id to be submitted?
CREATE TABLE `clients` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(50) NOT NULL,
PRIMARY KEY (`id`)
);
CREATE TABLE `clients_address` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`address_line_1` varchar(30) NOT NULL,
`address_line_2` varchar(30) NOT NULL,
`address_line_3` varchar(30) NOT NULL,
`town` varchar(30) NOT NULL,
`county` varchar(30) NOT NULL,
`postcode` varchar(8) NOT NULL,
`email` varchar(50) NOT NULL,
`tel` varchar(13) NOT NULL,
`contact_name` varchar(40) NOT NULL,
`client_id` int(11) NOT NULL,
`default_address` BOOLEAN NOT NULL DEFAULT 0,
FOREIGN KEY (client_id) REFERENCES clients(id),
PRIMARY KEY (`id`)
);
INSERT INTO `clients` (`id`, `name`) VALUES (1, 'First Client');

Answer 1

In your clients_address Table schema client_id int(11) NOT NULL, set. But when you insert a Address then you don't set value against client_id and client_id can't be NULL
Probably solutions
Set client_id in Address insert query
In your table schema client_id allow NULL or set a default value

Answer 2

You need to be sure that "client_id" is sent. Check with your Debug Kit bar on History, select the POST request, and then go to Sql log.
There must be a query like this:
INSERT INTO clients_address (
client_id, address, modified
)
VALUES
(
61, 'my address', "123..."
)
If not maybe something is wrong with your Form.
Your query must be something like this:
INSERT INTO clients_address (address_line_1, ..., contact_name, CLIENT_ID, default_address)
VALUES (:c0, :c1, :c2, :c3, :c4, :c5, :c6, :c7, :c8, :c9)
If you are adding addresses standalone (addresses controller add method), you must stipulate "client_id" manually on Form, or from a hidden field based on a parameter, with Cake bake it will make a list of Clients on Add and Edit methods.
If you are adding the address from Client Form as an association, on CakePHP docs are some good examples https://book.cakephp.org/3.0/en/views/helpers/form.html#creating-inputs-for-associated-data