mailcore2 imap Error Domain=MCOErrorDomain Code=5 - ios

Question

I in turn to the making relevant mailcore2 problems, based on past errors, and all of the share, or didn't find the solution to this problem below, so the problem I have encountered redistribution, also hope to get more help, thank you!
Mailcore2 using the code below：
self.imapSession = [[MCOIMAPSession alloc] init];
self.imapSession.hostname = hostname;
self.imapSession.port = 993;
self.imapSession.username = username;
self.imapSession.password = password;
if (oauth2Token != nil) {
self.imapSession.OAuth2Token = oauth2Token;
self.imapSession.authType = MCOAuthTypeXOAuth2;
}
self.imapSession.connectionType = MCOConnectionTypeTLS;
MasterViewController * __weak weakSelf = self;
self.imapSession.connectionLogger = ^(void * connectionID, MCOConnectionLogType type, NSData * data) {
#synchronized(weakSelf) {
if (type != MCOConnectionLogTypeSentPrivate) {
NSLog(#"event logged:%p %i withData: %#", connectionID, type, [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
}
}
};
// Reset the inbox
self.messages = nil;
self.totalNumberOfInboxMessages = -1;
self.isLoading = NO;
self.messagePreviews = [NSMutableDictionary dictionary];
[self.tableView reloadData];
NSLog(#"checking account");
self.imapCheckOp = [self.imapSession checkAccountOperation];
[self.imapCheckOp start:^(NSError *error) {
MasterViewController *strongSelf = weakSelf;
NSLog(#"finished checking account.");
if (error == nil) {
[strongSelf loadLastNMessages:NUMBER_OF_MESSAGES_TO_LOAD];
} else {
NSLog(#"error loading account: %#", error);
}
strongSelf.imapCheckOp = nil;
}];
When I use iOS8.1 equipment, error message as follows, the console output：
checking account
2015-02-15 10:58:36.712 MailCoreTest[11971:2988194] event logged:0x166a4d50 0 withData: * OK [CAPABILITY IMAP4 IMAP4rev1 IDLE XAPPLEPUSHSERVICE ID UIDPLUS AUTH=LOGIN NAMESPACE] QQMail IMAP4Server ready
2015-02-15 10:58:36.821 MailCoreTest[11971:2988194] event logged:0x166a4d50 0 withData: (null)
2015-02-15 10:58:36.824 MailCoreTest[11971:2988128] finished checking account.
2015-02-15 10:58:36.825 MailCoreTest[11971:2988128] error loading account: Error Domain=MCOErrorDomain Code=5 "Unable to authenticate with the current session's credentials." UserInfo=0x16596ec0 {NSLocalizedDescription=Unable to authenticate with the current session's credentials.}
But when I use iOS8.0 devices, console to print the results are as follows:
checking account
2015-02-15 11:22:53.249 MailCoreTest[7853:1742121] finished checking account.
2015-02-15 11:22:53.249 MailCoreTest[7853:1742121] error loading account: Error Domain=MCOErrorDomain Code=1 "A stable connection to the server could not be established." UserInfo=0x17e50ab0 {NSLocalizedDescription=A stable connection to the server could not be established.}
Please help me, I contact with Objective - C time is short, but I must do my best to be aggressive, still hope to give a detailed solution, sincere thank you once again, hard work！

Answer 1

Yes its an authentication issue, I had same issue with my app but it was working fine before.
After I got this error, I checked my gmail account and there was an email from Google with subject "Suspicious Sign in prevented" and This sign in was of CA, USA. Actually My Application was under review so it was rejected for this reason.
Then I found that gmail is disabling unauthorised IPs.
You have to enable the 2 step verification for the gmail account to resolve this and generate an app specific password. Use that password in your app and It'll work fine.
Follow below google link to generate application specific password.
https://support.google.com/mail/answer/1173270?hl=en