I host my WordPress (v5.4.2) blog on 000webhost.com and I am unable to save any post with emoji characters. I get this error Updating failed. Could not update post in the database

I have tried changing these lines in wp-config.php

define( 'DB_CHARSET', 'utf8mb4' );

define( 'DB_COLLATE', 'utf8mb4_unicode_ci' );

I also migrated all my tables in MySQL to utf8mb4_unicode_ci with the below step.

But none of these worked, what I am missing? Please help My WordPress version: 5.4.2

wp_encode_emoji()