Getting error while changing status of an order Magento 1.9.4

While changing the status of an order or creating the shipment, I am getting below error:

Cannot save shipment.

I have checked the exception log and found the below message.

exception ‘PDOException’ with message ‘There is no active transaction’ in /home/fashionstore/public_html/fashionstore/lib/Zend/Db/Adapter/Pdo/Abstract.php:314

I have debugged the error and found that it is coming from

$ shipment->getOrder()->setIsInProcess(true);

Please tell me the reason for the issue, I am not able to change the status of any of my orders.