NEHotspotConfigurationManager unable to Join

I am using NEHotspotConfigurationManager to connect wifi programmatically. Its an open Network without any password I am using below code:

     if (@available(iOS 11.0, *)) {


   NEHotspotConfiguration *config = [[NEHotspotConfiguration 
 alloc]initWithSSID:SSIDName];


            [NEHotspotConfigurationManager.sharedManager applyConfiguration:config completionHandler:^(NSError* error) {
                if (error) {
                       printf([error description]);   
                }
                else
                {
                      printf(@"success");
                }
            }];

I am connecting to the hostpot/access point of one device, but every time I am getting an error of unable to join but in response it goes to success as the error is nil. Is there any thing I need to add in configuration or add in setting or am I missing anything ?

PS: The wifi is of IOT device

-Thanks in advance

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