State-Pruning

You ran a query against a slightly older block, and instead of an answer you got this:

missing trie node 2bca...e91f (path ) state 0x2bca...e91f is not available

Or a nearby historical-query failure such as:

header not found

missing trie node specifically means the state needed to answer your query is unavailable. header not found can also come from a bad block reference, an unsynced endpoint, or provider retention behavior, so treat it as a related symptom rather than the exact same error. This post explains what the state trie is, why a full node prunes it, exactly when you will trip missing historical state, and how to fix it; at the end we look at why an archive node, ideally one you do not have to operate, is the only real cure.