Added remark

app/src/main/java/eu/faircode/email/Core.java

@@ -644,6 +644,7 @@ class Core {
                             // Move: NO [CANNOT] Operation is not supported on mailbox
                             // Move: NO [ALREADYEXISTS] Mailbox already exists
                             // Copy: NO Client tried to access nonexistent namespace. (Mailbox name should probably be prefixed with: INBOX.) (n.nnn + n.nnn secs).
+                            // Copy: NO Message not found
                             // Add: BAD Data length exceeds limit
                             // Add: NO [LIMIT] APPEND Command exceeds the maximum allowed size
                             // Add: NO APPEND failed: Unknown flag: SEEN