What is the SR number?
Is ePO upgrade to 4.5 from previous version or it's fresh install?
If upgrade then please remember that the products will not be supported as per KB#:KB66145.
SR# : 3-1393767155
its not an upgrade, its a fresh install.EPO was working good, the error appeared suddenly.
Well , the issue was resolved, It resolved restarting the Epo and SQL Services.