Microsoft Foundry: Agent Stopped Working — Cannot Invoke Connected Agent

Problem description

I am experiencing an issue where my Foundry agent has stopped working. Specifically, I cannot invoke the connected agent, and attempts to start a new chat in the Azure AI Foundry Playground result in an InternalServerError with the message 'Unable to get resource information.'

Environment

Azure AI Foundry; the affected experience is the Playground / agent chat flow used to start a new conversation; no specific region, SKU, subscription, resource name, or deployment name provided in the case details.

What I've already tried

I have attempted to reproduce the issue by starting a new chat in the Playground, which consistently failed with the same InternalServerError. I checked the browser network trace and confirmed the failure occurs during the backend request to resolve the agent conversation. No additional logs, diagnostics, or configuration changes have been recorded. I reviewed general self-help guidance for Foundry failures, including endpoint and API validation, region support, and network settings, but have not completed specific checks.

Current status

Currently, the main issue is that the agent chat flow in Playground returns an InternalServerError when fetching resource information. I am seeking assistance to diagnose and resolve the underlying cause, including whether the problem affects all agents or only specific projects, and what configuration or access issues might be involved.