@1nf1n1t3 Thank you for reaching out to us!
As far your question: No. The machines which you want to fail back from Azure have to be able to talk to the configuration server on-prem. Additionally, the on-prem CS/PS won’t work if it can’t talk to Azure anyways.
Reference doc: https://learn.microsoft.com/en-us/azure/site-recovery/failover-failback-overview#reprotectionfailback
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