If your candidate has any issues accessing test links start by working through these solutions.
Devices & Software Requirements
These tests work best on laptops, MacBooks, PC’s iPads and tablets. Some smart-phones will work, but their screens are typically too small for you to navigate the test effectively. Do not intend to complete the test on a smartphone.
The best browser to use is always Chrome
My Test Won’t Load – I Get an Error Message
If clicking the test link results in you getting an error message right away, or after entering your bio-data, make sure you are using Chrome as your browser, then copy & paste the test link (url) directly into the Chrome browser rather than clicking on it.
You can't open a link you intend for a candidate, for example to complete any bio-data in advance. The link can be accessed only once.