I had the same problem:
ERROR: Unable to start MySQL server: mysqld: Character set 'UTF-8' is not a compiled character set and is not specified in the '/usr/share/mysql/charsets/Index.xml' file mysqld: Character set 'UTF-8' is not a compiled character set and is not specified in the '/usr/share/mysql/charsets/Index.xml' file I edited the mysqld.cnf and changed
character-set-server = UTF8 to
character-set-server = utf8mb4