Elastic is up and running:_cat/indices?v
health status index uuid pri rep docs.count docs.deleted store.size pri.store.size
green open .kibana cBSx-QSrQfyC_KqD04Forg 1 1 1 0 7.7kb 3.8kb
green open .security UFth26cVRSaiSMqrCOcq3A 1 1 5 0 37.1kb 18.5kb
I assume that you properly installed xpack following elastic instruction (when you try to access data,you should be prompted for credentials)
Username and password for elastic are case sensitive (already faced the issue).
Regarding the web config, you can try to revert your changes on web config and remove/install again Orchestrator UiPlateform.msi on the Orchestrator, keeping the existing database and entering the Elastic search authentication detail using the wizzard (handled since 2018 version) (note that there is no validation made by the wizzard on the correctness of the creds supplied)
It usually does work since the pattern should be default-MM implying that you are using the default tenant.
What do you get the you use the command above (from elastic search) it should give you the list of available indices autogenerated by the Orchestrator?