Error
Mailbox name contains invalid characters:
Cause
Some defective IMAP servers may list folders but later fail to return content from these folders. This typically affects IMAP implementations that cannot handle special characters in folder names.
For example, a defective IMAP server may list a folder called "A - B", but fail to return content for this folder because of the special character ("-" in this example).
The problem may also affect folders with trailing spaces. For example, a defective IMAP server may list a folder called "A/B " but fail to return content for this folder because of the trailing space.
Resolution
This error will result in a failed migration because an entire folder cannot be processed, to fix this issue you can consider the following solutions:
- Renaming mailbox folders to avoid special characters.
- Specifying a folder exclusion filter to exclude these folders from the migration.
- Upgrading the IMAP system to see if a more recent version solves the problem.