I tried modifying the request so it would include a 3600 second expire time. (minutes - 1 hour) as shown in the example it returned an error the parameter was invalid. It shows - but as "null"

curl --data-binary '{"id":"curltext","method":"addrequest","params":{"amount":"3.14","exp":"3600","memo":"test"}}' http://127.0.0.1:7777

{"error": {"message": "Invalid parameters.", "code": -32602}, "jsonrpc": "2.0", "id": "curltext"}[

This is Electrum client daemon - not server - Linux (CentOS 7) - not Windows - it runs and returns a request fine without the "exp" parameter