Syntax error or access violation: 1115 Unknown character set: utf8mb4

Go to config/database.php and replace these two lines with these

'charset' => 'utf8', 'collation' => 'utf8_unicode_ci',

Go to config/database.php and replace these lines. That's it

'charset' => 'utf8',  
'collation' => 'utf8_unicode_ci',