You can try the following steps.
Check the logs: The first step is to look at the SRM logs for more information about the error. Logs often provide valuable clues as to what might be causing the problem. Look for specific error messages that might indicate why the failback failed.
Configuration Validation: Make sure that all required settings are correctly configured on the SRM. This includes connection details, networking, storage mapping, and so on. A repeated configuration can lead to failback issues.
Connectivity test: Verify that there is proper connectivity between the primary and secondary sites. This includes checking network connectivity, firewall and DNS.
Available resources: Make sure that the necessary resources, such as storage and compute resources, are available at the target site to accommodate the virtual machines you are trying to failback.
Attempt to failback in smaller steps: If you are trying to failback multiple virtual machines, try to failback in smaller steps. This can help isolate specific issues.
Updates and Patches: Make sure you are using the latest version of SRM and that all patches are applied. Known issues are sometimes fixed in updates.
Technical Support: If you are unable to resolve the issue on your own, please do not hesitate to contact VMware technical support. They are experienced in dealing with a variety of issues and can provide personalized assistance.
Backup: Before taking any more drastic action, back up your critical data. This is important to avoid losing data if something goes wrong during the troubleshooting process.
