Please refer to this spreadsheet from the Clark County Election Department’s website to determine if you need to add or fix your signature on your mail-in ballot:
https://docs.google.com/spreadsheets/d/1PWen22PZL8meBHmPZsPGpxl8TlJixcSW8kXzT1CT7f8/edit?usp=sharing
If your name is on this list, please contact the Election Department right away:
Phone: (702) 455-VOTE (8683)
MailBallotRequest@ClarkCountyNV.gov
You only have through November 12th to fix your ballot.
Vote Nevada 
I have already called to verify my name and ballot. And I’m still on this list. Was notified that my ballot signature did not match however I did already call to verify myself.
Thanks for letting us know; there seems to be a lag in the Election Department updating the list. Can you share when you called to verify?