diff -r b58463d7dc8e -r 69eaef18b01b client/src/sagas/networkSaga.js
--- a/client/src/sagas/networkSaga.js	Tue Jun 27 10:54:04 2017 +0200
+++ b/client/src/sagas/networkSaga.js	Tue Jun 27 11:38:26 2017 +0200
@@ -1,6 +1,9 @@
 import * as types from '../constants/actionTypes';
 import { all, call, fork, race, take, cancelled, put, select } from 'redux-saga/effects'
 import config from '../config';
+import * as persistConstants  from 'redux-persist/constants';
+import jwt_decode from 'jwt-decode';
+import moment from 'moment';
 
 // Utility function to delay effects
 function delay(millis) {
@@ -11,39 +14,51 @@
 }
 
 function pingServer(client, token) {
-  if(token) {
-    const timeout = new Promise((resolve, reject) => {
-      setTimeout(reject, config.networkStatusTimeout, 'request timed out');
-    });
+  const decodedToken = jwt_decode(token);
+  const currentTs = moment.now()/1000;
+
+  const timeout = new Promise((resolve, reject) => {
+    setTimeout(reject, config.networkStatusTimeout, 'request timed out');
+  });
+
+  if((decodedToken.exp-currentTs) < 300) {
     return Promise
       .race([timeout, client.post('/api/auth/refresh/', { token })]);
   } else {
-    return Promise.reject({ error: 'No token in the store'})
+    // We do a GET because a HEAD generate a preflight CORS OPTION request. The GET does not.
+    return Promise
+      .race([timeout, client.get('/api/auth/user/')]);
   }
 }
 
-// Fetch data every 20 seconds
 function* pollData(context) {
+  const token = yield select(state => state.token);
+  // No token : we wait for a login
+  if(!token) {
+    yield take(types.AUTH_LOGIN_SUCCESS);
+  }
   try {
-    yield call(delay, config.networkStatusInterval);
-    const token = yield select(state => state.token);
     const res = yield pingServer(context.client, token);
     yield call(context.callback, true);
-    yield put({
-      type: types.AUTH_STORE_TOKEN_ASYNC,
-      token: res.token,
-    });
+    if(res.token) {
+      yield put({
+        type: types.AUTH_STORE_TOKEN_ASYNC,
+        token: res.token,
+      });
+    }
   } catch (error) {
     yield call(context.callback, false);
-    // if the error is that there is no token, then we know we have to wait for a login
-    if(error.error && error.error === 'No token in the store') {
-      yield take(types.AUTH_LOGIN_SUCCESS);
-    } else if (error.non_field_errors &&
+    //TODO: This is ugly...
+    if ((error.non_field_errors &&
       error.non_field_errors &&
       error.non_field_errors.length &&
       error.non_field_errors.length > 0 &&
       ( error.non_field_errors[0] === 'Signature has expired.' ||
-        error.non_field_errors[0] === 'Refresh has expired.' )
+        error.non_field_errors[0] === 'Refresh has expired.' )) ||
+      (error.detail && (
+        error.detail === 'Signature has expired.' ||
+        error.detail=== 'Refresh has expired.'
+      ))
     ) {
       yield put({
         type: types.AUTH_DEAUTHENTICATE
@@ -55,12 +70,21 @@
       // if there is a token : this was a LOGIN, set status to ok
       // if there is no token : this was a LOGOUT, set status to ko and wait for login
       const token = yield select(state => state.token);
-      if(token) {
-        yield call(context.callback, true);
-      } else {
-        yield call(context.callback, false);
-        yield take(types.AUTH_LOGIN_SUCCESS);
-      }
+      yield call(context.callback, Boolean(token));
+    }
+  }
+}
+
+function* callDelay(context) {
+  try {
+    yield call(delay, config.networkStatusInterval);
+  } finally {
+    if (yield cancelled()) {
+      // pollDate cancelled
+      // if there is a token : this was a LOGIN, set status to ok
+      // if there is no token : this was a LOGOUT, set status to ko and wait for login
+      const token = yield select(state => state.token);
+      yield call(context.callback, Boolean(token));
     }
   }
 }
@@ -68,9 +92,13 @@
 // Wait for successful response, then fire another request
 // Cancel polling if user logs out or log in
 function* watchPollData(context) {
+
+  //wait for the state to be rehydrated
+  yield take(persistConstants.REHYDRATE);
+
   while (true) {
     yield race([
-      call(pollData, context),
+      all([call(pollData, context), call(callDelay, context)]),
       take(types.AUTH_LOGOUT),
       take(types.AUTH_LOGIN_SUCCESS)
     ]);