MySQL Error 3926 – ER_CLIENT_PRIVILEGE_CHECKS_USER_DOES_NOT_EXIST

MySQL Error Message

PRIVILEGE_CHECKS_USER for replication channel ‘%s’ was
set to `%s`@`%s`, but this is not an existing user.

Reason for the Error

ER_CLIENT_PRIVILEGE_CHECKS_USER_DOES_NOT_EXIST
was added in 8.0.18.