rest - Why do i get HttpMediaTypeNotAcceptableException? -

i have springboot rest controller:

@restcontroller public class usercontroller {     @autowired userrepository userrepository;      @requestmapping(value = "/account/{userid:.+}", method = requestmethod.get)     public httpentity<account> getaccountbyuserid(@pathvariable string userid) {         if(userid == null) {             return new responseentity<>(httpstatus.bad_request);         }         account user = userrepository.findonebyuserid(userid.tolowercase());         if(user == null) {             return new responseentity<>(httpstatus.not_found);         }         return new responseentity<>(user, httpstatus.ok);     } } 

note @pathvariable definition weird because spring mvc @pathvariable dot (.) getting truncated.

this call works , receive 200 status code lovely json: http://.../account/scarlett.j@myplace.com

however call http://.../account/scarlett.j@myplace.com.au returns status code 406 , debug logs show message "org.springframework.web.httpmediatypenotacceptableexception: not find acceptable representation"

why , how fix it? thanks.