This error is due to the ePortal windows user account password having been changed or modified, or the password set in the Windows user account was not configured to be the same password in the web config file. To rectify this, please do as follows in 2 places:
Computer Management
Go to the server, Computer Management, Local Users and Groups.
Click on Users and right-click Properties.
Under the Member Of, verify if there is an ePortal user with an Administrator member role.
Right-click the ePortal and Set Password.
WebConfigEditor
Search IIS, expand Sites, expand Default Website.
Right-click eportal, select Explore.
Click on the eportalv2 folder and go to the Utilities folder.
Run WebConfigEditor.exe and click the Load button to load the WebConfig file from the eportalv2/web folder.
Under the ASP.Net/IIS tab, update the Identity_Password and Save (update the same password you set in computer management).
If you encounter a permission error, assign full permission to the eportalv2 folder in Step 3, then try again from Step 5 to Step 6.