ERROR:unauthorized when trying to register clients to Satellite 6.12.2

This was working two days ago, but it is no longer working. Bottom line is that the

curl -sS 'https://satellite.mylocaldomain.com/register?...'

command I generated on 4/3 was able to successfully register new hosts. I used Ansible to perform registration using the curl command via the shell module. Today, I am getting:

ERROR:unathorized

when I try to run it via Ansible or via command-line on the host I am trying to register with Satellite. I've checked, and I'm not using any third-party libcurl libraries. I have verified that I can register the hosts using the katello-ca-consumer-latest.noarch.rpm process, but that is deprecated, so I don't want to use that method for the remaining hosts I need to register.

I haven't changed anything since yesterday, so I am perplexed as to why it was working yesterday, but it isn't working today.

I have tried using the --insecure method, too, as a test, but the results were the same.