LiteLLM - Custom Endpoint Connection Failing with 500 Internal server error

[baburaj5]

Hello,
We have deployed the LiteLLM in Kubernetes Cluster and configured the Custom endpoint. When testing the connection, getting the below error. Endpoint URL redirects to different location for authentication.

litellm.exceptions.APIConnectionError: litellm.APIConnectionError: CustomException - . Received Model Group= "modelname"
2025-06-04T05:28:34.247223403Z Available Model Group Fallbacks=None LiteLLM Retried: 1 times, LiteLLM Max Retries: 2
2025-06-04T05:28:34.267435452Z REACHES async_pre_call_hook, call_type: acompletion
2025-06-04T05:28:34.267510546Z INFO: 100.80.188.154:51536 - "POST /chat/completions HTTP/1.1" 500 Internal Server Error

Tried adding the pass-through endpoint but still its not working.

Same endpoint working fine when we use the Curl.

Could someone help/guide on the issue.