WordPress API db_insert_error

I want to publish content on my site with WordPress’s wp-json/wp/v2/posts API, but I am getting the following error. How can I solve the problem?

{ code: ‘db_insert_error’, message: ‘The post could not be inserted into the database.’, data: { status: 500 }, additional_data: [ ‘WordPress database error: The following field could not be processed: post_content. The value sent may be too long or contain invalid data.’ ] }