"Provider not set or invalid" when run it locally

[vsmelov]

Thanks you for the great example!
When I try to run it, I get this error in JS console

core.js:1427 ERROR Error: Uncaught (in promise): Error: Provider not set or invalid
Error: Provider not set or invalid
    at Object.InvalidProvider (errors.js:34)
    at RequestManager.sendAsync (requestmanager.js:76)
    at Object.get [as getNetwork] (property.js:116)
    at eval (contract.js:487)
    at new ZoneAwarePromise (zone.js:890)
    at Function.detectNetwork (contract.js:478)
    at Function.deployed (contract.js:426)
    at ExchangeService.refreshBalanceTokenInExchange (exchange.service.ts:32)
    at new ExchangeService (exchange.service.ts:25)
    at _createClass (core.js:10915)
    at _createProviderInstance$1 (core.js:10889)
    at resolveNgModuleDep (core.js:10874)
    at NgModuleRef_.get (core.js:12110)
    at resolveDep (core.js:12608)
    at createClass (core.js:12470)
    at createDirectiveInstance (core.js:12315)
    at createViewNodes (core.js:13776)
    at callViewAction (core.js:14210)
    at execComponentViewsAction (core.js:14119)
    at createViewNodes (core.js:13804)
    at createRootView (core.js:13665)
    at callWithDebugContext (core.js:15090)
    at Object.InvalidProvider (errors.js:34)
    at RequestManager.sendAsync (requestmanager.js:76)
    at Object.get [as getNetwork] (property.js:116)
    at eval (contract.js:487)
    at new ZoneAwarePromise (zone.js:890)
    at Function.detectNetwork (contract.js:478)
    at Function.deployed (contract.js:426)
    at ExchangeService.refreshBalanceTokenInExchange (exchange.service.ts:32)
    at new ExchangeService (exchange.service.ts:25)
    at _createClass (core.js:10915)
    at _createProviderInstance$1 (core.js:10889)
    at resolveNgModuleDep (core.js:10874)
    at NgModuleRef_.get (core.js:12110)
    at resolveDep (core.js:12608)
    at createClass (core.js:12470)
    at createDirectiveInstance (core.js:12315)
    at createViewNodes (core.js:13776)
    at callViewAction (core.js:14210)
    at execComponentViewsAction (core.js:14119)
    at createViewNodes (core.js:13804)
    at createRootView (core.js:13665)
    at callWithDebugContext (core.js:15090)
    at resolvePromise (zone.js:824)
    at resolvePromise (zone.js:795)
    at eval (zone.js:873)
    at ZoneDelegate.invokeTask (zone.js:425)
    at Object.onInvokeTask (core.js:4744)
    at ZoneDelegate.invokeTask (zone.js:424)
    at Zone.runTask (zone.js:192)
    at drainMicroTaskQueue (zone.js:602)
defaultErrorLogger @ core.js:1427
ErrorHandler.handleError @ core.js:1488
next @ core.js:5498
schedulerFn @ core.js:4339
SafeSubscriber.__tryOrUnsub @ Subscriber.js:239
SafeSubscriber.next @ Subscriber.js:186
Subscriber._next @ Subscriber.js:127
Subscriber.next @ Subscriber.js:91
Subject.next @ Subject.js:56
EventEmitter.emit @ core.js:4319
(anonymous) @ core.js:4775
ZoneDelegate.invoke @ zone.js:392
Zone.run @ zone.js:142
NgZone.runOutsideAngular @ core.js:4701
onHandleError @ core.js:4775
ZoneDelegate.handleError @ zone.js:396
Zone.runGuarded @ zone.js:158
_loop_1 @ zone.js:702
api.microtaskDrainDone @ zone.js:711
drainMicroTaskQueue @ zone.js:610
Promise.then (async)
scheduleMicroTask @ zone.js:585
ZoneDelegate.scheduleTask @ zone.js:414
Zone.scheduleTask @ zone.js:236
Zone.scheduleMicroTask @ zone.js:256
scheduleResolveOrReject @ zone.js:871
ZoneAwarePromise.then @ zone.js:981
PlatformRef.bootstrapModule @ core.js:5569
(anonymous) @ main.ts:11
../../../../../src/main.ts @ main.bundle.js:296
__webpack_require__ @ inline.bundle.js:55
0 @ main.bundle.js:311
__webpack_require__ @ inline.bundle.js:55
webpackJsonpCallback @ inline.bundle.js:26
(anonymous) @ main.bundle.js:1
core.js:1427 ERROR Error: Uncaught (in promise): Error: Provider not set or invalid
Error: Provider not set or invalid
    at Object.InvalidProvider (errors.js:34)
    at RequestManager.sendAsync (requestmanager.js:76)
    at Object.get [as getNetwork] (property.js:116)
    at eval (contract.js:487)
    at new ZoneAwarePromise (zone.js:890)
    at Function.detectNetwork (contract.js:478)
    at Function.deployed (contract.js:426)
    at ExchangeService.refreshBalanceEtherInExchange (exchange.service.ts:40)
    at new ExchangeService (exchange.service.ts:28)
    at _createClass (core.js:10915)
    at _createProviderInstance$1 (core.js:10889)
    at resolveNgModuleDep (core.js:10874)
    at NgModuleRef_.get (core.js:12110)
    at resolveDep (core.js:12608)
    at createClass (core.js:12470)
    at createDirectiveInstance (core.js:12315)
    at createViewNodes (core.js:13776)
    at callViewAction (core.js:14210)
    at execComponentViewsAction (core.js:14119)
    at createViewNodes (core.js:13804)
    at createRootView (core.js:13665)
    at callWithDebugContext (core.js:15090)
    at Object.InvalidProvider (errors.js:34)
    at RequestManager.sendAsync (requestmanager.js:76)
    at Object.get [as getNetwork] (property.js:116)
    at eval (contract.js:487)
    at new ZoneAwarePromise (zone.js:890)
    at Function.detectNetwork (contract.js:478)
    at Function.deployed (contract.js:426)
    at ExchangeService.refreshBalanceEtherInExchange (exchange.service.ts:40)
    at new ExchangeService (exchange.service.ts:28)
    at _createClass (core.js:10915)
    at _createProviderInstance$1 (core.js:10889)
    at resolveNgModuleDep (core.js:10874)
    at NgModuleRef_.get (core.js:12110)
    at resolveDep (core.js:12608)
    at createClass (core.js:12470)
    at createDirectiveInstance (core.js:12315)
    at createViewNodes (core.js:13776)
    at callViewAction (core.js:14210)
    at execComponentViewsAction (core.js:14119)
    at createViewNodes (core.js:13804)
    at createRootView (core.js:13665)
    at callWithDebugContext (core.js:15090)
    at resolvePromise (zone.js:824)
    at resolvePromise (zone.js:795)
    at eval (zone.js:873)
    at ZoneDelegate.invokeTask (zone.js:425)
    at Object.onInvokeTask (core.js:4744)
    at ZoneDelegate.invokeTask (zone.js:424)
    at Zone.runTask (zone.js:192)
    at drainMicroTaskQueue (zone.js:602)
defaultErrorLogger @ core.js:1427
ErrorHandler.handleError @ core.js:1488
next @ core.js:5498
schedulerFn @ core.js:4339
SafeSubscriber.__tryOrUnsub @ Subscriber.js:239
SafeSubscriber.next @ Subscriber.js:186
Subscriber._next @ Subscriber.js:127
Subscriber.next @ Subscriber.js:91
Subject.next @ Subject.js:56
EventEmitter.emit @ core.js:4319
(anonymous) @ core.js:4775
ZoneDelegate.invoke @ zone.js:392
Zone.run @ zone.js:142
NgZone.runOutsideAngular @ core.js:4701
onHandleError @ core.js:4775
ZoneDelegate.handleError @ zone.js:396
Zone.runGuarded @ zone.js:158
_loop_1 @ zone.js:702
api.microtaskDrainDone @ zone.js:711
drainMicroTaskQueue @ zone.js:610
Promise.then (async)
scheduleMicroTask @ zone.js:585
ZoneDelegate.scheduleTask @ zone.js:414
Zone.scheduleTask @ zone.js:236
Zone.scheduleMicroTask @ zone.js:256
scheduleResolveOrReject @ zone.js:871
ZoneAwarePromise.then @ zone.js:981
PlatformRef.bootstrapModule @ core.js:5569
(anonymous) @ main.ts:11
../../../../../src/main.ts @ main.bundle.js:296
__webpack_require__ @ inline.bundle.js:55
0 @ main.bundle.js:311
__webpack_require__ @ inline.bundle.js:55
webpackJsonpCallback @ inline.bundle.js:26
(anonymous) @ main.bundle.js:1
web3.service.ts:59 Refreshing accounts```

what can I do?