The network said Tuesday that "a record amount of activity" overloaded its online and telephone voting systems after Monday's show.
"Some viewers reported experiencing difficulties registering their votes for the Dancing with the Stars finale, which affected each finalist equally," ABC said in a statement. "The issue was promptly addressed" and voting times were not extended.
Finalists Grey, Bristol Palin and Kyle Massey performed their last dances for viewer votes on Monday's episode, which count for half of their overall scores toward the title.
Grey comes into Tuesday's season finale in first place. The 50-year-old actress and her professional partner, Derek Hough, earned a perfect score of 60 for their two dances on Monday's show. Massey finished in second place with 56 points, while Palin landed in third with 52 points. All three will perform two dances on Tuesday's show before a new "Dancing" champ is named.
Palin has made it to the finals despite so-so and at times poor performances. She said it was challenging to overcome the flurry of media coverage that erupted when she was voted in over Brandy -- who had received a perfect score for her tango -- on the hit show, prompting some viewers to question the veracity of the "Dancing" voting system. At the announcement of Brandy's elimination on that particular episode, Brandy was speechless, and Hough's jaw quite literally dropped.
Palin's improbable run to the finals has been championed by websites such as conservative blogger Kevin DuJan's Hillbuzz.org, who have been leading get-out-the-vote campaigns for Palin and partner Mark Ballas.
"Are you planning on hosting a Team Bristol Monday Night Dancing Watch party?" reads a post on his website. "You ... can actually vote together and send Bristol over the top ... while sending Leftist heads into meltdown."
"Dancing" executive producer Conrad Green said it would be fair game if Palin's voters send her to victory Tuesday.
"If she ends up winning the show, she ends up winning the show because more people decided to make the effort to vote for her -- for whatever reason they're passionate about her -- than they did for other people, and that is a valid part of the show," he said.
Though Palin said on Monday's episode that "there's lots of haters out there that are waiting for me to fail," the 20-year-old single mom said after the show that she feels she and Ballas deserve to win.
"We've been working our butts off," she said.
Grey said she won't consider the mirrorball trophy until Tuesday's dances are done.
"I think it's bad juju," she said after earning a perfect score Monday.
Massey and his partner, Lacey Schwimmer, said they've been having so much fun dancing together, they can hardly believe they actually have a chance at the title.
"We have a one-in-three shot," Schwimmer said.
"It'll be crazy if we win," Massey said. "I'll be excited. I'll probably do the worm again."
The 19-year-old Disney Channel star did the retro dance move during his freestyle routine on Monday's show.
The judges will have the final say Tuesday. Viewer voting is closed, but each contestant will add the judges' scores for their two dances Tuesday to their overall Monday totals. The dancer with the highest combined total of judges' points and viewer votes will become the new "Dancing" champ.
ABC is owned by The Walt Disney Co. Disney is the parent company of ABC 30.