How to Resolve Azure Slot Swap Errors During Ongoing Operations

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If you’re trying to swap your staging and production slots for your Azure app and see the message “Cannot modify this site because another operation is in progress,” it means another process is currently running that’s blocking the swap. Here’s a simple plan to fix this issue:

First, check the Activity Log in the Azure Portal. Go to your App Service, then click on Activity Log. Look for any entries that say an operation is ongoing, failed, or stuck. Usually, these operations should finish within 10 to 30 minutes, but sometimes they may hang or timeout. If you see an ongoing task related to certificate creation or renewal, that’s likely what’s holding up the swap.

Next, verify the status of any certificates on your app. In the Azure Portal, go to your App Service, then navigate to TLS/SSL settings and Managed certificates. Check if your certificate is “Issued,” “Pending,” or shows any errors. Make sure auto-renewal is enabled if you want it to get renewed automatically. Also, ensure that your custom domain’s TLS/SSL binding isn’t pending or in progress. If you’re using HTTP validation for your SSL certificate, ensure your site isn’t blocking access to the /.well-known/ path, since this is needed for the validation.

If everything looks correct but the issue persists, try swapping the slots using Azure CLI. Sometimes, the command line tool can bypass problems faced in the portal. Use this command, replacing <app-name>, <resource-group>, and other placeholders with your actual details:

az webapp deployment slot swap –name –resource-group –slot stage –target-slot production

Also, double-check your deployment slot settings. Make sure any certificate-related settings are marked correctly—either as slot-specific or global—because wrong configuration here can cause issues during the swap.

If you need to avoid downtime and the certificate creation is blocking the swap, there’s a workaround: temporarily remove the custom domain and TLS binding from the staging slot before swapping. After the swap is complete, you can re-add the binding.

For more information, you can review the official documentation on Managed Certificates and slot deployment:

If these steps help or if you have further questions, please let us know. If this information was useful, kindly upvote—it helps others facing the same issue!