Dear Christian, I've just submitted a PR [1] that fixes an issue occurring with some combination of browser/proxy and that we stumbled upon in 9.5.3 beta. I attach a picture that shows how it looks like in DBA. To make error disappear it's sufficient to put a . in the query input. We propose to make query parameter optional in signature of RestXQ handling that call. Let us know if any further info is required. Regards, Marco. [1] https://github.com/BaseXdb/basex/pull/2030