Why My iPhone isn't Updating?

Hi,Im From Nepal.As we know the recent iOS(11) update is available for ios devices.I have an iPhone 6splus but whn i try to update to latest software from the Settings It keeps saying UNABLE TO CHECK FOR UPDATE and also ERROR OCCURED WHILE CHEKING FOR A SOFTWARE UPDATE...

Is my iPhone only Experienced this problem because on my iPad it shows iOS 11 update and it gets updated..

Please Help Me on This

APPLE🙂