A refused large message now tells you why instead of vanishing

When something goes wrong with a message — you lack permission for it, or nothing is listening at the address you sent it to — the mesh sends you back an error report that quotes the message it is about, so you can see which one failed.

For a very large message that quote was the problem. The report carried a full copy of the message inside it, which made the report at least as large as the message — so a report explaining that a 37 MB import could not be delivered was itself a 37 MB message, and it failed to be delivered for exactly the same reason. Nothing was logged on your side and nothing came back: the request simply sat there until it timed out, with no message and no explanation of what had happened to it.

Reports about messages that are too big to carry now quote the message's size and its type instead of its contents, so the report gets through. You see which message failed and how far over the limit it was, which is what you need in order to act — usually by importing or writing in smaller batches.

Nothing changes for ordinary errors. A report about a normal-sized message still quotes it in full, exactly as before; the summary only replaces content that would have cost you the report itself.