When upgrading my vRA lab to 7.6 I had a problem with the embedded vRO instance complaining that the Authentication Provider settings were not configured. Using the Reset button in vRO Control Center and updating the Authentication Provider settings didn’t resolve it either and I was unable to launch the new vRO HTML 5 client.

What worked for me was to reset the Authentication Provider settings via the command line of the vRA appliance using steps from the vRA official documentation. The documentation is from 7.4 and the procedure is used to resolve a different issue, but the fix still worked.
Before performing any of the steps here make sure you note the warning in the VMware documentation:
This procedure resets tenant and group authentication back to the default settings. If you have customized your authentication configuration, note your changes so that you can re-configure authentication after completing the procedure.
1.Stop the vRO services:
service vco-server stop
service vco-configurator stop
2.Reset the authentication provider
Run the command/var/lib/vco/tools/configuration-cli/bin/vro-configure.sh reset-authentication
Delete the vco-registration-id file /etc/vco/app-server/vco-registration-id
Reconfigure the vco-service by running the command vcac-vami vco-service-reconfigure
3. Start the vRO services:
service vco-server start
service vco-configurator start
When you log back in to the Control Center the Authentication Provider settings will be set back to the default of vsphere.local as the tenant and vsphere.local\vcoadmins as the group.

You can now update the settings back to the previous configuration and should be able to launch the vRO HTML 5 client.
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