How to solved Unknown collation: 'utf8mb4_unicode_520_ci'

You can solve this by finding

ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_520_ci;

in your .sql file, and replacing it with

ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci;

Save the file and upload it. 

Thanks:)