Error: Failed to download the Vault Credentials file.

@Kimberly Salazar Sorry for the delayed response!

I answered a similar question couple of years ago here - https://zcusa.951200.xyz/en-us/answers/questions/1052547/not-able-to-download-vault-credential-file the suggestions were helpful resolving the issue. If this doesn't help, try the following:

1. If your machine is behind a corporate proxy or a firewall, make sure the proxy settings are correctly configured for the MARS agent and that the required ports (usually ports 443 for HTTPS) are open.
2. Ensure that the MARS agent can reach Azure's servers without any blocking firewall rules or proxy settings interfering. For Azure Backup, the agent requires outbound access to the following endpoints:
   • *.backup.windowsazure.com
   • *.backup.windows.net
   • *.core.windows.net
3. Some antivirus or security software can interfere with the download process. Try temporarily disabling your antivirus or security software and attempt to download the credentials file again.
4. Ensure you're running the latest agent version. Find the latest version in the portal, or download from here.
5. If these steps doesn't help resolve the issue, try rebooting the server once and then proceed with MARS installation.

If issue persists, the best option would be to contact Azure technical support team by raising a support request. The ticket enables you to work closely with the support engineers and get a quick resolution to your issue.

Here is the link - https://docs.microsoft.com/en-us/azure/azure-portal/supportability/how-to-create-azure-support-request to create support case.

Hope this helps!