The migration of existing Site24x7 accounts to Zoho Single Sign-On is highly secure and there is no possibility of your account getting compromised.
Site24x7 is part of the Zoho family. We already share the same data center as Zoho, whose Single Sign On platform we are migrating to. In Zoho, we have our own Identity Access Manager software developed by our engineering teams and not by any third party authentication service. Hence your data will never leave our servers, at any point in migration.
Even in a rare scenario of a failed migration, it just means that a particular account has failed to move to the Single Sign-On platform. Your Site24x7 account and the data in it will remain the same. Hence you don't have to worry about an account compromise during this migration.