Ever wondered how to fix this error?
First you have to enable the extbase debugger by adding below line to the setup field of your static template:
config.contentObjectExceptionHandler = 0
After that open the page that raised the error. Now it will reveal the cause.
Sometimes TYPO3 will still not show the error. In that case you could do the following:
Go to the TYPO3 installation tool.
Select: All Configuration
Search for: debugExceptionHandler
Empty the value
Search for: productionExceptionHandler
Empty the value
Now try again and check the webserver error log.