While trying to index a document, if ElasticSearch throws following exception: elasticsearch.exceptions.AuthorizationException: AuthorizationException(403, 'cluster_block_exception', 'blocked by: [FORBIDDEN/12/index read-only / allow delete (api)];') then, this means that ElasticSearch has cluster-wide locked writes to all indices. As a temporary solution, you can unlock writes to the cluster (all indexes) using: curl -XPUT -H "Content-Type: application/json" http://localhost:9200/_all/_settings -d '{"index.blocks.read_only_allow_delete": null}' but, this might still result in locking of indices because underlying problem has not been fixed. Most often it is caused by exceeding the disk watermark / quota. In its default configuration, ElasticSearch will not allocate any more disk space when more than 90% of the disk are used overall (i.e. by ElasticSearch or other applications). We can reduce this watermark extremely low using: curl