Could you please let us know from which Redmine version you upgraded the application from? Did you follow our documentation page that explains how to upgrade it?
Did the migration to the new database return any error message?
We have a Support Tool that will gather relevant information for us to debug the issue. 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.