Your chances of having a vote-by-mail ballot rejected in Miami-Dade are among the highest in the state – especially if you are a black or Hispanic voter, a study by ACLU Florida found.

Statewide, one percent of VBM ballots are rejected. In Miami-Dade, the rejection rate is 1.9 percent - the third highest rate in the state.

For black and Hispanic voters, 2.7 percent of mail-in ballots are rejected. That's the second-highest rate in the state for black voters.

Ballots can be rejected for two reasons: voters either failed to sign the envelope or the signature did not match the one on file.

Christina White, Miami-Dade supervisor of elections, said she did not know why the county she oversees rejected such a relatively large share of ballots.

“I can’t really say why. We educate all of our voters equally. This information is on the ballot itself,” she said. “We would love for it to be zero percent. We don’t like rejecting ballots and we really go above and beyond to accept all of them.”

It would be wrong to assume a large share of older voters in Miami-Dade boosts the rejection rate because, perhaps, older voters have more trouble following the instructions. The ACLU-Florida study found voters under 22 years old were eight times more likely to have their vote rejected than those 65 or older.

Two voters who failed to sign their ballots in a recent election told NBC 6 investigators they were sure they had signed them.

But when White’s office pulled their envelopes, it was clear they had not.

Nor did they return an affidavit to cure their ballot, which is sent to everyone whose ballot is rejected.

Last week, White and two judges reviewed nearly 1,000 ballots that had questionable signatures, accepting almost every one that was even a close call.

“We don’t like rejecting any ballot,” White said. “But if you don’t sign or your signature doesn’t match, we are required by law to reject it.”