Firstly - it's important to point out that ePO 4.5 is end-of-life, and you should definitely think about upgrading to a supported version.
This type of error is almost always caused by a problem accessing the DB. In the information you have provided, it appears that ePO is configured to access SQL using an account called epoadmin - but it also looks like epoadmin is an ePO account.
Are you sure that there is an SQL account called epoadmin with the correct permissions?
What happens if you try using the sa account, or a domain admin account, in the Configure Database Settings page?
Select all in ePO login page and paste into notepad and check at last it will give you exact error message.
Issue seems missing some .xml files in ePO installation directory which is in Catlina folder. Compare current extensions (Program Files\McAfee\ePolicy Orchestrator\Server\conf) with respective .xml file (Catlina folder). And check which are missing.
You can create missing .xml files by copying existing other .xml with editing.
This error occurs when there was a focereboot happen to your ePO server.