This is actually a calva issue. I asked the same question on the calva channel on slack an got some very helpful support. They even updated the calva homepage afterwards (see the notice box): Connect the REPL - Calva User Guide
Clava: “You must have a project file, such as
project.cljfor Leiningen ordeps.ednfor Clojure CLI, in the directory opened in VS Code in order for jack-in to work.”
If this does not solve your problem you can find a link to the calva slack channel and maybe you can address your problem there.