> For the complete documentation index, see [llms.txt](https://docs.mobb.ai/mobb-user-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mobb.ai/mobb-user-docs/common-troubleshooting-scenarios/broker-cannot-reach-scm.md).

# Broker & Tokens - Broker can't reach the SCM

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This scenario applies **only to on-premises deployments** that use the [Mobb Broker](/mobb-user-docs/more-info/mobb-broker.md).
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**Symptoms**

* The broker starts but never establishes a working tunnel to the SCM.
* Connectivity works only after network/firewall changes.

**Likely cause**

The broker client must be allowed to reach both the Mobb Broker Server and your internal SCM. Corporate firewalls, or a required outbound HTTPS proxy, can block the tunnel.

**Resolution**

1. Ensure outbound connectivity from the broker host to the Mobb Broker Server is allowed by your firewall.
2. If your network requires an outbound proxy, configure the optional proxy environment variables (`FRP_PROXY_URL`, `TARGET_PROXY_URL`) as described in the [Mobb Broker guide](/mobb-user-docs/more-info/mobb-broker.md#explanation-of-the-environment-variables).
3. If your SCM uses a self-signed or internal certificate, set `TARGET_DISABLE_CERT_VALIDATION=true`.

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Still stuck? Contact <support@mobb.ai>.
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