Riposte solution
The specified collation/comparator for an IMAP SORT or SEARCH is not supported by the server. In simpler terms, the server can't sort or search with that ordering. If you explicitly requested a comparator (which is rare via high-level APIs), try a different or no comparator. Usually, the default sorting should work. Adjust your search/sort request and try again.
Quick facts
- Provider
- IMAP
- Endpoint / surface
- IMAP Protocol
Why it happens
[Protocol-level condition per RFC/extension]
How to fix it
[Adjust client behavior per RFC semantics; often retry or change command/parameters]