`docker login registry1.dso.mil` fails to verify certificate

When I try to docker login into the registry, using the Username and CLI Secret found on Harbor:

I get the following error:

(main-env) ➜ docker login registry1.dso.mil                                       
Username: connor.williams.sedaro
Password: 
Error response from daemon: Get "https://registry1.dso.mil/v2/": tls: failed to verify certificate: x509: certificate signed by unknown authority

I am currently unable to pull images due to this.

Perhaps relatedly, I see a banner announcement saying:

ATTENTION: Immediate action is required to maintain compatibility with P1 services. Please visit https://p1notifications.dso.mil and see the "DSO.MIL Certificates Renewal" announcement under the "Notifications" section for more details.

However, when I go to that URL I get an error saying that I'm not authorized to view that resource. So if that page does contain instructions on how to resolve this error, I'm unable to view them.