It is most likely that you need a browser add-on installed.

To fix this, look towards the top of the browser and find a bar that says:

"This website wants to run the following add-on: 'Provision Networks Load and License Manager Client from 'Provision Networks'..."

All you need to do is click on the bar and allow it to download and install the add-on. After the add-on is installed you should be able to login using SureDesk™.