TIC TCP Conn Failed

I am trying to connect to our webservice server vai MDM (Mobile Iron) tunnel. I am getting this error.

2019-05-31 09:44:47.346402-0500 xxxxx[3938:1731358] TIC TCP Conn Failed [3:0x2805215c0]: 12:8 Err(-65554)

2019-05-31 09:44:47.348358-0500 xxxxx[3938:1731358] Task <F00B000D-3B15-48CF-B053-6F6880F8A583>.<3> HTTP load failed (error code: -1003 [12:8])

2019-05-31 09:44:47.348682-0500 xxxxx[3938:1731358] Task <F00B000D-3B15-48CF-B053-6F6880F8A583>.<3> finished with error - code: -1003

2019-05-31 09:44:47.351787-0500 xxxxx[3938:1731366] Custom Error: Error Domain=NSURLErrorDomain Code=-1003 "A server with the specified hostname could not be found." UserInfo={NSUnderlyingError=0x283e5b900 {Error Domain=kCFErrorDomainCFNetwork Code=-1003 "(null)" UserInfo={_kCFStreamErrorCodeKey=8, _kCFStreamErrorDomainKey=12}}, NSErrorFailingURLStringKey=https://internalWebServiceURL.com:8448/index.php/auth, NSErrorFailingURLKey=https://internalWebServiceURL.com:8448/index.php/auth, _kCFStreamErrorDomainKey=12, _kCFStreamErrorCodeKey=8, NSLocalizedDescription=A server with the specified hostname could not be found.}

This is my code for TCP/IP connection. My iOS version is 11.3

NSURLSessionDataTask *requestTask = [[NSURLSession sharedSession]

dataTaskWithRequest:theRequest completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {

if (!error) {

NSHTTPURLResponse *httpResp = (NSHTTPURLResponse*) response;

if (httpResp.statusCode >= 200 && httpResp.statusCode < 300) {

NSError *jsonError;

id array = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:&jsonError];

if (!jsonError) {

dispatch_async(dispatch_get_main_queue(), ^{[self datareturn: array];});

}

}

else if(httpResp.statusCode == 500) {

self.title = @"No Data Found";

[self errorReturned:@"Server error occurred, please try again later."];

}

else {

self.title = @"No Data Found";

[self errorReturned:@"Unknown error occurred1, please try again later."];

}

}

else {

NSLog(@"Custom Error: %@", error);

[self errorReturned:@"Unknown error occurred2, please try again later."];

}

}];

[requestTask resume];

Any help would be appreciated.