microsoft-365-l1-desktop-support-send-receive-issues-troubleshooting

Microsoft-365-L1-Desktop-Support-guide

This article is designed as a practical, real-world L1 Desktop Support guide focused on troubleshooting Microsoft Outlook within a Microsoft 365 and Exchange Online environment. The goal is to help support engineers understand not just what to fix, but how to think during real helpdesk scenarios — from basic configuration to admin-level checks. Each section is structured around common ticket categories faced in enterprise environments. Whether you are preparing for an IT support role, improving troubleshooting workflow, or strengthening Microsoft 365 operational knowledge, this series will provide structured, actionable guidance. The content bridges the gap between end-user issues and Microsoft 365 Admin Center/Exchange Online workflows used by support teams daily. Outlook License Issue

I will write article on each topic for single single blog -

I’ll break into real helpdesk categories:

1. Account & License Management
2. Outlook Configuration
3. Send/Receive Issues
4. Profile & OST/PST Issues
5. Performance Issues
6. Mailbox & Storage
7. Archive & Backup
8. Exchange Admin Checks
9. Authentication/Login Problems
10. Common Errors & Fixes

Today we will see step by step Account & License Management  

Outlook is opening but not sending or receiving emails.

As per ITIL approach -

Step 1 - user verification 
step 2 - Initial L1 checks
step 3 - TroubleShooting
step 4 - Escalation 

🔹 Step 1 — User Verification

First I will ask:

Since when issue started?
Are you able to send but not receive or both not working?
Are other users facing same issue?
Are you using VPN?
Any recent password change?
Are you getting any error message?

🔹 Step 2 — Basic L1 Checks

Check internet connectivity
Check Outlook status bar (Working Offline / Disconnected)
Restart Outlook & system
Verify Outlook profile logged in
Check mailbox storage full or not
Try Outlook Web Access (OWA)

👉 Very important enterprise step:

 
If OWA works → Outlook client issue.

🔹 Step 3 — Technical Troubleshooting

Send test email internally & externally
Check account configuration (Exchange / IMAP / SMTP)
Disable add-ins
Run Outlook in safe mode

outlook /safe
Recreate Outlook profile

OR

 

🔑 Credential Fix

 
(Clear cached credentials (Credential Manager)

Control Panel → Credential Manager

Remove:

MicrosoftOffice / Outlook Credentials

Re-login

👤 Profile Repair (VERY COMMON FIX)

Control Panel → Mail → Show Profiles

✔ Add New Profile
✔ Set as Default
✔ Configure account again


Step 4 — Escalation

If still issue:
Server issue
Mail flow issue
License issue
Exchange backend issue

👉 Escalate to Messaging / O365 Team.

🎤 🎯 Interview Ready Short Answer (Professional)

 

You can say:

“First I will verify when the issue started and confirm whether Outlook Web is working to identify if the issue is local or backend. Then I will perform initial checks like internet connectivity, Outlook connection status and mailbox size. After that I will troubleshoot by disabling work offline mode, clearing credentials, checking Outbox, running Outlook in safe mode and recreating the Outlook profile. If the issue is related to Exchange server or mailbox corruption, I will escalate to L2 or Exchange team with complete troubleshooting details.”

Disclaimer