How do I convert a MySQL database from utf8mb4 to utf8 encoding?

It is totally essential to use utf8mb4 for your site to be secure and bug free in all wordpress versions since 4.2 and probably before that. You need to upgrade your mysql software to a newer version, or change whatever is need in its configuration to support it.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)