We have a Support Tool that will gather relevant information for us to analyze your configuration and logs. Could you please download and execute it on the machine where the stack is running by following the steps described in the guide below?
How to Run the Bitnami Support Tool
Please note that you need to paste the code outputted by the tool in your reply.
Apart from this information, could you please let us know if you made any change in the configuration files of the application or if you installed a theme, plugin or extension before running into this issue?