Read the article. It states pretty clearly that the printing machines that print the ballots is printing them too light for the tabulation (counting) machines to read properly. But, the ballot can still be read by the voter, and they can cast their ballot. Only instead of their vote being counted by a machine, now there is a chance it may have to be counted by hand since the machines cannot read it. Think back to the 2000 election and the "hanging chad", where the machines couldn't properly count the ballots, so they were counted by hand.
People can still vote. Their vote will still be counted. There is no reason to keep the polls open past the original cutoff time. All it basically means is that the poll workers will have to stay a bit later and work a bit longer to count all the ballots.