[Bug]: Cannot connect SMTP Provider

Preflight Checklist

• I could not find a solution in the documentation, the existing issues or discussions
• I have joined the ZITADEL chat

Environment

Self-hosted

Version

v4.0.0-rc.2

Database

PostgreSQL

Database Version

16.3

Describe the problem caused by this bug

We have a problem with our Mailjet smtp integration.

We have a Kubernetes cluster with nginx ingress installed. If I have a local docker container running a Zitadel instance, I have no problem with Mailjet. But as soon as the Zitadel instance is installed via helm on our cluster, then we will receive this error when we test the smtp provider.

RpcError(UNKNOWN): Http response at 400 or 500 level, http status code: 0

To reproduce

Screenshots

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Expected behavior

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Operating System

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Relevant Configuration

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Additional Context

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