You can check the requirements the latest Technical Requirements here. Please make sure you meet those requirements, in order to make sure you will be able to access the OnVUE system on the day of your exam. Note as well that:

• Corporate firewalls (including VPNs) or proxies often cause this delivery method to fail. We recommend testing on a personal computer. Work computers generally have more restrictions that may prevent successful delivery. Please take your exam in a setting without a corporate firewall.
• The current System Check does not look at anything outside of testing the internet connection, camera and microphone. The current System Check would not recognize or see a firewall or Windows version that may be set up on the candidate device, and which would not allow the OnVUE application on the day of the exam.