Dnf update issues

Hello there,

I was on RHEL 8 for the last two years and decided to upgrade to RHEL 9 yesterday. For a brief moment everything was fine: system has been registered, subscription was attached, I did enable BaseOS, AppStream and CodeReady Builder repos, and even successfully performed a 'dnf update' command once. But unfortunately, few hours later I've started to receive the following message whenever I try to perform 'dnf update':

Errors during downloading metadata for repository 'codeready-builder-for-rhel-9-x86_64-rpms':
- Curl error (91): SSL server certificate status verification FAILED for https://ru-by-exceptions.cdn.redhat.com/content/dist/rhel9/9/x86_64/codeready-builder/os/repodata/repomd.xml [No OCSP response received]
Error: Failed to download metadata for repo 'codeready-builder-for-rhel-9-x86_64-rpms': Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried

I was hoping that this is a temporary issue with server's expired certificate, since similar issues did happen on RHEL 8 several times, but 16 hours later the problem is still there and I'm starting to think that probably I should search for the cause on my side. Any suggestions on what could be done?

At this point I did try to:
Set sslverify=0 in /etc/dnf/dnf.conf
dnf clean all
Unregister the system, detach and reattach subscription.
But nothing helped.