Free-Busy Not Working
Calendar availability not syncing.
Check relationship, directory sync, HTTPS reachability.
Hybrid Exchange: Prevent $15K–$50K monthly dual-licensing costs
Rapid diagnosis for free‑busy failures, mailbox migration blockages, and HCW issues. 15–40 minute resolution prevents migration timeline slippage and project cost escalation.
Covers federation trust issues, OAuth authentication failures, organization relationship misconfigurations, migration endpoint connectivity, and HCW prerequisite failures. Prevents split mailbox data (eDiscovery gaps), cross-forest collaboration breakage, and extended dual-licensing periods. Includes safe rollback procedures for migration batch failures.
Hybrid Problem Categories
Select the issue affecting your hybrid environment. Free-busy problems prevent calendar visibility between on-premises and cloud users. Migration issues occur when moving mailboxes from on-prem to Exchange Online. HCW failures prevent initial hybrid configuration or updates to the hybrid topology. All guides include validation steps and safe rollback procedures.
Mailbox Migration Stuck
Migration batch stalled or failing.
Check source mailbox, throttling, logs, and sync.
Hybrid Configuration Wizard Failed
HCW errors or prerequisite failures.
Review logs, connectivity, firewall, and cert trust.
When to Use This Section
Use these guides when encountering issues in coexistence environments where Exchange Online and on-premises Exchange servers must interact. Common failures include Hybrid Configuration Wizard errors, free/busy calendar lookup failures between cloud and on-prem users, mailbox moves that stall during migration batches, mail routing breaks after federation trust changes, or Autodiscover pointing to wrong endpoints. These diagnostics assume HCW has been run at least once and cover post-deployment operational issues.
Full Documentation
Detailed procedures with safe rollback steps.