This situation is quite concerning! From the error I would guess the admin identities got removed from recent account aggregation in the authoritative source. Are you facing the issue in production tenant?
The fact that all administrators are simultaneously locked out suggests this isn’t a standard account lockout scenario.
Given the severity and security implications, I strongly recommend you contact SailPoint Support immediately rather than trying to troubleshoot this through community channels. This type of complete tenant lockout affecting all admins requires urgent professional attention.
Open an P1 / high priority support ticket with SailPoint - emphasize that all administrators are locked out. Document everything: when the lockout started, exact error messages, any recent terminations of high privileged user, any unusual activity before the incident. Notify your internal security team - this could potentially be a security concern.
No thankfully it is not our customer tenant but our internal Partner Tenant. Since the API is still accessible, i am now trying to create a new CSV source & Identity Profile and load new admin identities again.