This issue happens when Internet Explorer security settings prevents internet cookies and cache from loading when opening the TMCM/Apex Central WebUI.
To solve this, add Control Manager URL in Trusted Sites.
Open Internet Explorer and go to Internet Options.
Go to the Security tab and select Trusted sites as the zone then click Sites.
In the Add this website to the zone field, enter the TMCM/Apex Central URL then click Add.
- Go to the General tab and delete the browsing history.
Close Internet Explorer and reopen the TMCM/Apex Central WebUI using an Internet Explorer browser.
- Verify if you can now log in.