When adding new NG hosting node to OA infrastructure, the task "Perform post web servers registration tasks on host1.example.com" fails with:
Configuration can not be assigned to web cluster
The configuration "NG Default Configuration" is not in "Applied" state.
Web hosting configuration "NG Default Configuration" is always applied by default to every Cloud Linux web server. In case it pending changes to be applied to web nodes OA configuration checked does not consider it as ready to be applied.
To resolve the issue navigate to "Services > Web Hosting > Manage Configurations > NG default configuration > Apply Changes" and wait for the corresponding tasks completion. After that the failed task can be resubmitted.