Help Center/ Server Migration Service/ FAQs/ Error Codes and Solutions/ SMS.6520 The source server is not available.
Updated on 2026-01-09 GMT+08:00

SMS.6520 The source server is not available.

Symptom

The migration task status is abnormal, and the error message "SMS.6520 The source server is not available." is displayed.

Possible Causes

This issue usually occurs in the following scenarios:

  • Scenario 1: The migration task is created through the server migration workflow on MgC. The source server failed the pre-migration environment check and is intercepted when the migration task is started.
  • Scenario 2: After the migration task starts and the network quality evaluation subtask is running, the source SMS-Agent disconnects from the SMS console.

Solution

The solutions are as follows: