Dont try to connect to imap when navigator is offline

src/js/email/email.js

@@ -1017,6 +1017,13 @@ Email.prototype.encrypt = function(options) {
 Email.prototype.onConnect = function(imap) {
     var self = this;
 
+    if (!self.isOnline()) {
+        // don't try to connect when navigator is offline
+        return new Promise(function(resolve) {
+            resolve();
+        });
+    }
+
     self._account.loggingIn = true;
 
     // init imap/smtp clients

test/integration/email-dao-test.js

@@ -293,6 +293,7 @@ describe('Email DAO integration tests', function() {
                             passphrase: testAccount.pass,
                             keypair: mockKeyPair
                         }).then(function() {
+                            sinon.stub(accountService._emailDao, 'isOnline').returns(true);
                             accountService._emailDao.onConnect(imapClient);
                         });
                     });

test/unit/email/email-dao-test.js

@@ -1956,6 +1956,7 @@ describe('Email DAO unit tests', function() {
 
             beforeEach(function() {
                 initFoldersStub = sinon.stub(dao, '_initFoldersFromImap');
+                sinon.stub(dao, 'isOnline');
                 delete dao._imapClient;
 
                 credentials = {
@@ -1968,6 +1969,7 @@ describe('Email DAO unit tests', function() {
                     uid: 123,
                     modseq: '123'
                 }];
+                dao.isOnline.returns(true);
                 authStub.getCredentials.returns(resolves(credentials));
                 imapClientStub.login.returns(resolves());
                 imapClientStub.selectMailbox.returns(resolves());
@@ -1990,6 +1992,16 @@ describe('Email DAO unit tests', function() {
                     done();
                 });
             });
+
+            it('should not connect when user agent is offline', function(done) {
+                dao.isOnline.returns(false);
+
+                dao.onConnect(imapClientStub).then(function() {
+                    expect(authStub.getCredentials.called).to.be.false;
+
+                    done();
+                });
+            });
         });
 
         describe('#onDisconnect', function() {