Whenever any special, primary, municipal or general election has been held and errors of commission or omission have occurred or have been made in connection with the preliminary requirements therefor or in the conduct thereof, and no action, contest or suit has been instituted concerning any such election, or its returns, or its certification, within one year from the date thereof, any such election, its return and the certification made thereon are hereby ratified and validated: Provided, however, This act¹ shall in no event disturb, affect or validate any election, its return or certification thereon, wherein legal proceedings relating thereto and involving fraud or any error, have already been instituted or are now pending.