If  you experience a blank screen during a LockDown Browser session, it's typically caused by one of the following:

1) Your computer or network is blocking access to one or more of our servers.

The best thing to do initially is to temporarily relax all anti-virus and firewall software, then try again. Be sure to increase the security of your anti-virus software afterwards. If this doesn't help, you should try using a different network, as the block may exist at the network level.

2) Your connection to the Moodle server may have been broken.

In this case, leaving the exam, reestablishing your connection and then re-entering the exam is the best strategy.

3) You have multiple monitors hooked up. This is not supported. Disconnect the additional monitors and open LockDown Browser up in the main monitor.