Ok, Found out to be a change in expression. A good explanation by @mmdemirbas here-
Password must be 8 characters including 1 uppercase letter, 1 special character, alphanumeric characters
( # Start of group
(?=.*\d) # must contain at least one digit
(?=.*[A-Z]) # must contain at least one uppercase character
(?=.*\W) # must contain at least one special symbol
. # match anything with previous condition checking
{8,8} # length at least 8 characters and also maximum of 8
) # End of group
My end expression now is-
((?=.*\d)(?=.*[A-Z]).{8,50})
Thanks everyone for stopping by.
working here- https://dotnetfiddle.net/lEFYGJ