In Magento 1.9.2.4 Invoice and Shipping Emails are not working

Question

I have recently upgraded to Magento 1.9.2.4. After upgrade, the invoice and ship emails are not working from the admin console. Clicking on 'Submit Invoice' (with 'Email copy of invoice' checked) takes to a blank 500 page.

After debugging, it seems that

$mailer->send() method is causing the issue. The method is not returning. The method is present in code/core/Mage/Sales/Model/Order/Invoice.php.

Any clue on what could be the issue ?

Answer 1

I was able to figure out after debugging the issue in more detail. The issue was happening since method

mb_convert_encoding (lib/Pelago/Emogrifier.php)

was not defined and the method was not returning. The email was not sent and the Invoice/Shipping page showed a 500 error page.

I used the following command and things started working fine:

yum install php54-mbstring

Thanks!