Not able to connect to MongoDB vCore cluster

Hello @Umer Ahmed

The error indicates that the cluster has exhausted its available client connection slots. Since both MongoDB Compass and your web application are affected, this is unlikely to be a Compass configuration or firewall issue.

Please check Azure Portal → your MongoDB vCore cluster → Monitoring → Metrics and review the connection count, CPU, memory, and server errors around the time the issue started. Azure Monitor metrics and client diagnostics can help confirm whether the connection limit was reached.

On the application side, verify that:

A single shared MongoClient instance is being reused rather than created for every request.

Connections, cursors, and sessions are closed correctly.

The driver’s connection-pool size is limited appropriately.

Idle connections have a reasonable maxIdleTimeMS.

Multiple application instances aren’t each creating oversized connection pools.

Restarting the web application or stopping the suspected rogue client may release its pooled connections. However, Microsoft Q&A contributors can’t restart an individual customer’s managed cluster. If no administrative connection remains available and the connections don’t clear, create an Azure support request under Help + support → Create a support request → Azure Cosmos DB/DocumentDB, and provide the cluster resource ID, UTC timestamps, region, exact error, and relevant metrics.

Scaling beyond the current M10 tier may provide additional capacity, but I’d first identify the connection leak or excessive pool configuration. Otherwise, the larger tier could eventually encounter the same issue.

Also, please avoid posting the full connection string or password publicly. Rotate the password immediately if either was exposed.

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