Thank you for your post!
I'm sorry for any inconvenience. My recommendation would be the following:
1. Clear cache and cookies from your primary browser, as a general precaution.
2. Close all open applications before attempting to launch the assignment.
3. Uninstall and reinstall Lockdown Browser, using this link: Install LockDown Browser in WileyPLUS
4. Restart your computer.
5. Temporarily turn off your anti-virus software, as it may be blocking the connection.
6. Try with another computer user account, or on a different computer if possible.
I hope these suggestions help! Ultimately, you might need to simply take a screen shot for your instructor to verify the issue you're encountering.
Please let us know if you have any questions. Have a nice evening!