You may get the error mentioned as the post heading while you backup using some automatic backup tools such as MySQL ZRM or mysqldump.Sometimes you will see that the even though adding the
entry in the MySQL server my.cnf file. The reason behind this is, you have to add the ‘max_allowed_packet’ entry in the client side as well. The default value for ‘max_allowed_packet’ at server is 1M and at the client is 16MB. The largest value for ‘max_allowed_packet’ value at client or server is 1G. Add the value appropriate for your situation and your backup should work well.