It's very likely the configuration of either your OpenID provider or in your XO plugin config. See our example with Keycloak: https://xen-orchestra.com/blog/xen-orchestra-5-80/#-openid-connect-support

It seems like you are confusing xcp-ng (the virtualization server) with XO (the VM for managing xcp-ng). Based on your earlier post, you needed to update XO, not xcp-ng. Therefore, you should be able to rerun your XenOrchestraInstallerUpdater script to update XO to the latest source commits.