This issue occurs due to changes made to the login endpoint for OSE.
Resolution
The new root path can be located under Cloud Director UI > More > Object Storage > Security Credentials. The value should be similar to https://<OSE FQDN>:443.
Note:
If you experience issues accessing the standalone portal endpoint (https://<OSE FQDN>/portal/login) this may be due to Local storage caching within your browser.
Clearing Local storage for a site may vary depending on your browser, please ensure to follow the relevant documentation from your browser developer.
The standalone portal is for troubleshooting and is not designed for access by tenant users.