Azure DevOps has two URL schemes:
dev.azure.com/<org> (new)
<org>.visualstudio.com (old)
While *.visualstudio.com addresses are considered legacy, they are still used in quite a lot of places.
I've received some reports from users that the new OIDC authentication isn't working with *.visualstudio.com addresses. I haven't got full logs to inspect at the moment, but I'm creating this issue as a placeholder in the meantime.