When Floridians vote by mail, they trust their vote will be received and that it will count. And growing numbers of voters are just fine with that. In the primary election, mail voting was the preferred option for 1.2 million Floridians, about one-third of those who voted.

There’s good reason to believe it will be even more popular for the Nov. 6 general election. Florida’s ballot will be long, with 12 proposed constitutional amendments, local referenda and candidates facing off in races for Congress and the Governor’s Mansion. Mulling over the choices at home makes sense — and is convenient.

Supervisor of Elections Wesley Wilcox went out of his way to emphasize, in the run-up to the primary, that all mail ballots count — in fact, absentee ballots are counted first. But there’s one important wrinkle. Some ballots can’t be counted at all — starting with the ones that never made it to voters. The next problem: Voters who don’t sign their ballots, or whose signature is significantly different from the one election offices have on file. Both will cause the ballot to be rejected. Florida law gives voters a chance to “cure” mistakes by verifying their ID with elections officials, and instructs supervisors to promptly notify voters that their ballots need attention. Some don’t follow through, meaning their votes can’t be counted.

That’s an issue across Florida, according to a new report by the University of Florida’s Political Science Department for the ACLU. It varies by county and demographic group, but statewide, a little more than 1 percent of mail ballots were rejected in the 2012 and 2016 presidential elections. That represents more than 50,000 votes cast but never counted. It wasn’t enough to make a difference in Florida’s presidential results either year, but plenty of downballot races in 2012 and 2016 were decided by a handful of votes.

In general, local officials seemed to do a better-than-average job of fixing vote problems. According to the ACLU report, Marion County was among the top 10 in fewest numbers of mail-in ballot rejected in both 2012 and 2016.

In some counties, however, the vote-rejection disparity was far greater. Some counties managed to fix most of their problem ballots; others had higher-than-normal rates of unfixed rejections. The report also reflects that minority voters and voters under the age of 30 were more likely to have their votes rejected.

Florida lawmakers should take a look at what the most successful counties are doing right, and use those county’s practices — in ballot design, voter education and follow-up — to set minimum standards for supervisors across the state. The state also needs to do a better job of collecting information on all mail ballots that can’t be counted, and why. And local elections officials should keep up the pressure on voters to update their signatures and addresses. Voting by mail is a great option for many voters, and it should be as secure as it is convenient.