Problem

When performing an attachment-only pre-migration using the Confluence Cloud Migration Assistant (CCMA), users can proceed without selecting any spaces. This leads to a generic "We can't communicate with your server" error, even if the authentication token is valid and the server connection is healthy. The error is misleading and does not guide the user to the actual root cause.

Steps to Reproduce

1. Attempt an attachment-only pre-migration in CCMA.
2. Do not select any spaces.
3. Proceed with the migration.

Expected Result

The UI should require users to select at least one space when performing an attachment-only migration, or provide a clear error message indicating that spaces must be selected.

Actual Result

A generic communication error is shown, which does not help the user resolve the issue.

Proposed Solution

• Make space selection mandatory for attachment-only migrations in CCMA.
• Alternatively, update the error message to clearly state that spaces must be selected for the migration to proceed.

References

• "We can't communicate with your server" starting attachment-only migration
• Migrate Confluence attachments in advance