HTTP ERROR 503 Problem accessing /. Reason: AuthenticationSupport service missing. Cannot authenticate request.

[jezwn]

Running the AEM instance I'm getting this error.

HTTP ERROR 503

I've tried opening the same via command line and tried deleting the index files and it's still the same. How can I resolve this? If the instance is corrupted somehow, how can I retrieve my project resources?

[Nirmal_Jose]

You can use oak run jar for reindexing -  How to complete full re-indexing in AEM

[hamidk92094312 · Accepted solution]

Checked the logs to verify the root cause. You may consider the following:

1. run a data store consistency check for potential corruption.

Fix Inconsistencies in the repository when SegmentNotFound Issue is reported in AEM 6.x

2. run index consistency check and potential corruption.

Use oak-run.jar to Manage Indexes

But the logs should give you some idea and I hope you have a backup.

[Love_Sharma]

For future visitors, Deleting repoinit folder from my AEM instance fixed this issue for me. Either you can run below command

 rm -rf crx-quickstart/launchpad/config/org/apache/sling/jcr/repoinit OR delete the folder manually. 

There are other ways too but this is the quickest I found