A user cannot log in to the POA Control Panel due to an error message like that provided below:
Error 'ERROR: could not access status of transaction 0;<br/> Error while executing the query' while ' DELETE FROM login_history WHERE login_time < ? AND user_id = ? AND logged_user_id = 0'
The SQL query in the error message above may be different in different cases.
There is no free disk space on the POA Database Server, so the PostgreSQL database server cannot operate properly. Use the df utility to check the amount of free disk space on the POA Database server.
Make sure that there is enough free disk space on the POA Database Server (at least a couple of GBs for system logs and database needs).