If any of the previous 10 problems (or others) happen, you will get a letter (yes, a real, in the US mail, aka snail-mail, PAPER LETTER) from the County Registrar of Voters, telling you:
- the reason your ballot was rejected,
- how you can fix the problem,
- the deadline for getting that done (it will be a VERY SHORT time)
So, after you send off your mail-in ballot:
- Go to Where's My Ballot and sign up to get updates on your ballot's status by text, email, and/or phone call
- Start checking your USPS mailbox every day for any letter from the Registrar of Voters. The letter could come anytime up through a month after election day. If you get one, Respond Immediately!
While mail-in ballots can't be counted until election night, they can be checked for errors starting a week before. So you could be contacted before election night if, for instance, there's no signature on your envelope. All they'll want you to do is come sign your envelope so it can be counted (yes, they really do want to help).
Since county elections officials are required by law to turn in the results of the ballot count by the 31st day after the election, rejections from a September 14th election, for example, must be resolved before October 15th.