If real user monitoring is enabled, additional privileges are required to read source maps.
To grant an APM Server user with the required privileges for reading RUM source maps from Elasticsearch directly without Kibana, assign the user the following privileges:
Allow APM Server to read RUM source maps from Elasticsearch
The above privileges should be sufficient for RUM source mapping to work properly as long as APM Server communicates with Elasticsearch successfully. If it fails, it may fallback to read source maps via Kibana if configured, which requires additional Kibana privileges. See RUM source map API for more details.