My fme flow 2025 server setup requires proxy settings to allow access to other ressources in the net.

This seems to cause trouble with the Elastic Writer (Elastic Cluster in this case).

When switching the proxy off, it is no problem to write content into a elastic index.

Switching the proxy on and putting the elastic server in the “no proxy for” list, leads to connection attempts to the proxy server and then timeouts, like here (10.150.0.77 is the proxy server):

2025-10-28 20:45:44|   1.2|  0.0|INFORM|ELASTICSEARCH_CLUSTER Writer: Feature Type Parameter 'fme_match_id_attribute' has value '_id' for feature type 'adressen_4326'
2025-10-28 20:45:44|   1.2|  0.0|INFORM|ELASTICSEARCH_CLUSTER writer: Opening cluster 'http://geogdiesp001.xxx:9200/'
2025-10-28 20:46:05|   1.2|  0.0|ERROR |ELASTICSEARCH_CLUSTER writer: JSON parsing error: boolean expected (at offset 2)
2025-10-28 20:46:05|   1.2|  0.0|ERROR |ELASTICSEARCH_CLUSTER writer: Failed to connect to 10.158.0.77 port 80 after 21004 ms: Could not connect to server
2025-10-28 20:46:05|   1.2|  0.0|ERROR |ELASTICSEARCH_CLUSTER writer: Unable to locate or open cluster 'http://geogdiesp001.xxx:9200/'.  Please ensure the cluster exists and is accessible.  Note that the ELASTICSEARCH_CLUSTER writer does not have the ability to create a new cluster.  However, creating the cluster manually in advance allows for subsequent data insertion

Any hints how to solve this riddle would be greatly appreciated