Dag that works well yesterday is not working the same way today

I recently created a DAG on Airflow and set it to parallel computing of tasks using PostgreSQL database. However today all my operators are failing (Even the Bash Operators using to print “Task Completed” messages). I tried changing the ports but it does not have any effect.
When I test the operators individually they work fine:
using command “airflow test DAGName OperatorName Data”, all operators are success, but overall the dag seems to fail.