Hello,
it might be technical issue for which you are not able to use the webpage. as of now close it and open it again after sometime when there will be less crowd like early morning, late night , lunch time.
try for it. it will do if there is server issue or server is down. if it is still not working then contact to the support team of NTA and ask to help you out. There is always a team who deals with these websites and it stores all the data in a storage. all these are linked and needs permission from the administration to allow to do any change in a server webpage.
so don't worry and follow steps. you will surely able to change it.
Hope it helps!
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