Unable to check for updates

Hello mbrandys3 and welcome to Apple Support Communities.

I see you are having difficulty connecting in order to install security updates? Is this happening with Safari?

If Safari says it can't establish a secure connection, or the website is using weak encryption - Apple Support

Cheers.

Hi mbrandys3.

Thanks for following up and confirming the error occurs when checking for an update from System Preferences.

Ensure your Mac is connected to a reliable network when attempting to update macOS. To further isolate this behavior, attempt updating macOS while your Mac is started in safe mode. Additionally, attempt updating macOS with a different user account. You can see those steps in the following support articles: Use safe mode to isolate issues with your Mac - Apple Support & How to test an issue in another user account on your Mac - Apple Support

If the issue persists, check to see if SOCKS Proxy is enabled within the network preferences. To do so, open System Preferences > Network, then select your active network interface. Click the Advanced button, click the Proxies tab, and then scroll down to see if SOCKS Proxy is enabled. If SOCKS Proxy is enabled, then it would be best to reach out to Apple Support for further assistance: Get Support

Cheers.

Hello. I wanted to add that the same issue is happening with me, after the 10.15.3 update was applied. Also, the update appears to have broken OpenVPN in some fashion.