Must Have Skills: Provide Tier 3/Tier 4 operational support for Exchange Online, including incident response, troubleshooting, and root-cause analysis. Administer user, shared, and resource mailboxes, including permissions, delegation, and access reviews aligned to least-privilege practices (RBAC). Troubleshoot mail-flow issues (NDRs, delays, routing, connectors, transport rules) and perform message trace and email header analysis. Support Outlook (Classic and New Outlook) issues including p