365 Mailbox dont show in backupset

Symptoms

The Office 365 backup set does not show the Exchange mailboxes when creating backup set.

Cause

It is an issue about permission for the backup set account, proxy or firewall is being used, plugin was not installed properly or DLL files overwritten by old versions.

Workaround

1. Ensure the Exchange dashboard is on green status or had no problems.

2. Ensure the backup set account has Global Administrator role and has licenses.

3. If using Proxy, configure the connection to use Proxy and open 443 (https, web SSL) port and 80 (http) port. Using netstat -an on the command prompt, check if the port 443 is in SYNC_SENT status, it means port 443 was blocked or port 80 is in TIMEOUT status and need to open the ports or use proxy server on the DS-Client configuration connection parameter.

4. Run the plugin on command prompt as an Administrator and check for error messages. Try to re-run again and ensure no errors.