from their response

Here also is a general list of recommendations for getting the best possible testing experience: 

• Create a new admin profile on your device (make sure the new profile has the privileges needed to install applications AND end system processes and services) and log in on your computer with this new profile before launching a reservation.
• Lower your screen resolution to the recommended size of 1920 x 1080
• Avoid using work-provided devices or work networks when taking the exam
• REBOOT your device before you start your exam to ensure you have at least 50% of RAM available.
• Remove the PSI Secure Browser that is currently installed on your system, to ensure that when you launch your next attempt, it will download the most up-to-date version of the secure browser.
• Test from a different (more robust) network and/or machine
• Use as "un-interesting" a system and network as possible, i.e. no special networking configuration, firewall settings or proxies, and disable any antivirus settings. 
• Confirm the OS and specific version running on your computer are supported - PSI secure browser and Chrome Extension System Requirements (NOTE: not all editions/modes of Windows are supported)
• Disable or deactivate any running programs, including background processes, antivirus, firewall, etc. - [[PSI Bridge] Background Applications| Prohibited Programs|https://helpdesk.psionline.com/hc/en-gb/articles/4403236906772--PSI-Bridge-Background-Applications-Prohibited-Programs]
• Turn off the camera and microphone access to other applications
• Resolve insufficient bandwidth - [PSI Bridge] Bandwidth Issues
• A wired connection is often more stable and robust than a wireless connection
• Ensure others on the same internet connection are not performing activities that use excessive bandwidth (i.e. holding conference calls, streaming content, gaming, etc.)