I also get the same error:
Migration failed
JSON Decoding Failure — Our AJAX request was expecting JSON but we received something else. Often this is caused by your theme and/or plugins spitting out PHP errors. If you can edit the theme or plugins causing the errors, you should be able to fix them up, but if not, you can set WP_DEBUG to false in wp-config.php to disable errors from showing up. (#144)
View error messages
Warning: fopen(/var/www/aber.vn/html/wp-content/uploads/aber_vn-migrate-20161221153819-b56t3.sql): failed to open stream: Permission denied in /var/www/aber.vn/html/wp-content/plugins/wp-migrate-db/class/wpmdb.php on line 2719
Warning: fclose() expects parameter 1 to be resource, boolean given in /var/www/aber.vn/html/wp-content/plugins/wp-migrate-db/class/wpmdb.php on line 2729
{“migration_state_id”:”585aa1ebd9c4b”}
