404 here is probably the binding hitting an entso-e url that moved or a bad area/document id, not your java certs anymore.
if certs were fixed and you got past the handshake, the next failure being 404 usually means the request reached their side and the path/params are wrong. check the binding docs for the current endpoint and your bidding zone code. sometimes their api returns 404 for an empty/invalid document instead of a nicer error.
paste the full thing config (token redacted) and the exact log line if you can.