“[G]o to your Polling Place to see whether or not your Mail In Vote has been Tabulated (Counted). If it has you will not be able to Vote & the Mail In System worked properly. If it has not been Counted, VOTE (which is a citizen’s right to do).”
FactCheck.org says: It is unnecessary, will likely cause long delays at polling places, and could be illegal. In many states, poll workers will not know whether a mail-in ballot has been received and accepted.