Recently While developing a custom module with cron job i faced an issue, my cron job was not executed successfully. When i inspected the cron_schedule table in database it shows the status as error and the below message was found in messages field.
‘Mage_Core_Exception’ with message ‘Invalid callback: mymodel/observer::observermethod doesn’t exist
My model class is not recognized. But i have my observer class in the Model directory. I have my config.xml as below
<cron_expr>*/5 * * * *</cron_expr>
Since iam using only the observer class in my model directory and not using any other model class i didnt
add any entry for model class in the config.xml. But Magento is looking for model class name. In case if your magento cron job is not working the solution is to add a model class configuration entry in config.xml above the crontab tag.