i am getting error on post method ionic(6) with capacitor angular(13)

Question

enter image description herevendor.js:139831 ERROR HttpErrorResponse {headers: HttpHeaders, status: 0, statusText: "Unknown Error", url: "http://localhost:8080/checkEmailExists", ok: false, …} error: ProgressEvent {isTrusted: true, lengthComputable: false, loaded: 0, total: 0, type: "error", …} headers: HttpHeaders {normalizedNames: Map(0), lazyUpdate: null, headers: Map(0)} message: "Http failure response for http://localhost:8080/checkEmailExists: 0 Unknown Error" name: "HttpErrorResponse" ok: false status: 0 statusText: "Unknown Error" url: "http://localhost:8080/checkEmailExists" proto: HttpResponseBase