A privately signed certificate will present your web browser with an error due to the browser not being able to determine whether the certificate is secure and safe. Making an exception to this certificate must be done on a case by case setup. Each web browser, Chrome, Firefox, Edge, etc, will need the exception as needed. You must ensure you know where you are going on the web when making the exception or you may end up at a malware or phishing type site.
Common website that the district will not have a "Publicly" signed certificate are listed below and should be considered safe.
https://iprint.usd405.com
https://filr.usd405.com
https://mobility.usd405.com
To add an exception to your browser see the following screen shots.
Chrome: Click on the Proceed to "URL" (UnSafe) option at the bottom of the screen.
Firefox: Click "Add Exception"
Edge: Click Continue to this webpage