Foreign key constraint is incorrectly formed / I can't create a VC, what's the problem?

Question

MySQL

I get an error while migrating

Foreign key constraint is incorrectly formed

I'm not strong in the database, tell me what I'm doing wrong.

public function safeUp()
    {
        $this->createTable('profile', [
            'id' => $this->primaryKey(),
            'surname' => $this->string()->notNull(),
            'name' => $this->string()->notNull(),
            'email' => $this->string()->notNull(),
            'gender' => $this->string()->defaultValue("MAN"),
            'birthday' => $this->date(),
            'telephone' => $this->string(),
            'site' => $this->string(),
            'role' => $this->string()->notNull(),
            'company' => $this->string(),
            'about' => $this->text(),
            'city' => $this->string(),
        ]);

        $this->addForeignKey(
            'fk-profile-id-user',
            'profile',
            'id',
            'user',
            'id',
            'NO ACTION',
            'CASCADE'
        );

        $this->addForeignKey(
            'fk-profile-email-user',
            'profile',
            'email',
            'user',
            'email',
            'NO ACTION',
            'CASCADE'
        );
    }

The first foreign key appeared, but there are problems with the second one. The types are identical for user.email and profile.email.

Answer 1

Has a unique index been created for the user.email field? The primary key can only point to a field that does not allow duplicate values.
But the situation itself, when two duplicate links are implemented between two tables for different pairs of fields, looks at least strange.