We are aware that, when using the standard access URL, users are getting a blank screen, instead of the login page.
We believe this is a PHP issue and are currently investigating.
In the mean-time please use https://vwm.overssl.net/admin/ with your standard credentials to gain access to the Admin Portal.
UPDATE (13:40 22/03/19) This issue has now been resolved. The problem was traced to PHP version state and should not re-occur.