[Where do states stand on voting rights for felons? Here’s a breakdown.]

Ms. Mason, who was sentenced to 60 months in jail for tax fraud and was released in early 2016, has said that she didn’t know that she wasn’t allowed to vote in that year’s presidential election. She cast a provisional ballot at her local church after being told that her name could not be found on the rolls. The ballot was never counted.

“Crystal’s name was purged from the rolls when she went to prison, but Crystal did not know that,” Ms. Grinter said in an interview on Tuesday.

Whether felons can vote varies state by state, and has become a contentious issue. More than six million Americans have been stripped of their voting rights because of felony disenfranchisement laws, according to the Sentencing Project, a nonprofit organization that works on criminal justice reform.

Two months ago, a petition was started online to have all charges against Ms. Mason, who is black, thrown out. In the petition her photo is placed next to a photo of Terri Lynn Rote, a white woman who was convicted of voter fraud in Iowa for trying to vote for President Trump twice. Ms. Rote was sentenced to two years’ probation and a $750 fine. The petition has over 38,000 signatures.

As she prepared to appeal the rejection of her motion for a new trial, Ms. Mason said she had high hopes.