Fixing:

ErrorException
Warning: Attempt to read property "post_type" on null.

Solution:

The error message you are seeing suggests that the $post object is null, which means that it was not able to retrieve the post object using the get_post() function.

Here are a few things you can try to resolve this issue:

Check if $post_id is valid: Make sure that $post_id is a valid post ID. You can check if it is by using the post_exists() function: