Foreign Key Constraint Violation for ManyToMany Mapping (Postgresql)

I have a bidirectional ManyToMany mapping, and I am trying to delete a post entity. When I delete it, the reference in the posts_categories table should also be removed. However, despite trying the following two approaches, it’s not deleting the reference, and I am receiving the error below. I am using postgresql and I did not find solution for my problem.

ERROR: The UPDATE or DELETE operation on the "posts" table violates the "fkq4402eed597exuj50g73c7kmg" foreign key constraint on the "posts_categories" table.

First Approach

@Entity
@Data
@Table(name = "posts")
public class PostEntity extends BaseEntity {

@ManyToMany
@JoinTable(
        name = "posts_categories",
        joinColumns = {@JoinColumn(name = "post_id")},
        inverseJoinColumns = {@JoinColumn(name = "category_id")})
private Set<CategoryEntity> categories = new HashSet<>();
...
} 


@Entity
@Data
@Table(name = "categories")
public class CategoryEntity extends BaseEntity {

@ManyToMany(mappedBy = "categories")
private Set<PostEntity> posts = new HashSet<>();    
}

Second Approach

@Entity
@Data
@Table(name = "posts")
public class PostEntity extends BaseEntity {

@ManyToMany
@JoinTable(
        name = "posts_categories",
        joinColumns = {@JoinColumn(name = "post_id")},
        inverseJoinColumns = {@JoinColumn(name = "category_id")})
private Set<CategoryEntity> categories = new HashSet<>();  
... 
}


@Entity
@Data
@Table(name = "categories")
public class CategoryEntity extends BaseEntity {

@ManyToMany
@JoinTable(
        name = "posts_categories",
        joinColumns = {@JoinColumn(name = "category_id")},
        inverseJoinColumns = {@JoinColumn(name = "post_id")})
private Set<PostEntity> posts = new HashSet<>();
}

My Service:

@Transactional
public Boolean deleteByUUID(UUID uuid) {
    Entity entity = postRepository.findByUuid(uuid).orElse(null);
    if (entity != null) {
        postRepository.delete(entity);
        return Boolean.TRUE;
    } else {
        return Boolean.FALSE;
    }
}