#1452 - Cannot add or update a Child Row: a Foreign key Constraint fails

Question

Personal talk I am having problems to create a foreign key in another table... You are giving this error:

#1452 - Cannot add or update a child row: a foreign key constraint fails....

Follow the command I’m doing to create foreign key:

ALTER TABLE cad_cadastro_cliente_acb ADD FOREIGN KEY (ID_SERV_CLIENTE_FK) REFERENCES cad_fluxo_servico(ID_CAD_FLUXO_SERVICO)

Follow the tables I created in the database:

CREATE TABLE cad_cadastro_cliente_acb(
ID_CLIENTE_ACB int(10) AUTO_INCREMENT, 
TIPO_PJ_PF_CLIENTE_ACB varchar(50), 
NOME_RAZAO_SOCIAL_CLIENTE_ACB varchar(100), 
CNPJ_CLIENTE_ACB varchar(50), 
CPF_CAD_ACB varchar(50), 
NOME_CONTATO_CLIENTE_ACB varchar(100), 
NOME_SOCIAL_CLIENTE_ACB varchar(100),
COMO_CONHECEU_CLIENTE_ACB varchar(10),   
ENDERECO_CLIENTE_ACB varchar(100), 
COMPLEMENTO_CLIENTE_ACB varchar(100), 
BAIRRO_CLIENTE_ACB varchar(100), 
CIDADE_CLIENTE_ACB varchar(100), 
CEP_CLIENTE_ACB varchar(100), 
UF_CLIENTE_ACB varchar(100), 
EMAIL_CLIENTE_ACB varchar(50), 
CONTATO01_CLIENTE_ACB varchar(15), 
CONTATO02_CLIENTE_ACB varchar(15), 
OBS_CLIENTE_ACB varchar(300),
ID_SERV_CLIENTE_FK INT(10) NOT NULL, 
USER_CAD_LOG varchar(20),
DATA_CAD_USER datetime,
PRIMARY KEY (ID_CLIENTE_ACB)
)ENGINE = innodb;



CREATE TABLE cad_fluxo_servico(
ID_CAD_FLUXO_SERVICO int(10) AUTO_INCREMENT,
SETOR_SERVICO varchar(20),
TITULO_SERVICO VARCHAR (100),
DESCRICAO_SERVICO VARCHAR(500),
RESPONSAVEL_SERVICO VARCHAR (50),
USUARIO_CAD varchar (50),
DATA_CAD_USER datetime,
PRIMARY KEY (ID_CAD_FLUXO_SERVICO)
)ENGINE = innodb;