Over the course of a few days, the president of the United States decided to sue the State of Nevada over the Directive ensuring Mail Voting. On August 5th, 2020 the president tweeted this out:

"Nevada has ZERO infrastructure for Mail-In Voting. It will be a corrupt disaster if not ended by the Courts. It will take months, or years, to figure out. Florida has built a great infrastructure, over years, with two great Republican Governors. Florida, send in your Ballots!"

Trump encouraged mail voting in Florida, but is suing the State of Nevada for ensuring it. 
Florida is guaranteed to win the 2nd term. The State Of Nevada should not be sued for following guidelines like other states. It's the United States, and we either stay united or we go separate ways, so if President Trump would like to sue the state of Nevada for allowing Mail-In ballots, he should legally sue Florida as well. Florida is seen as a must-win state for Trump and is governed by a Republican while Nevada's governor is a Democrat.
 The Nevada Republican Party organized a Tuesday protest in Carson City and Las Vegas.
In Reno, protesters don't want the ballots to be sent out to voters.  
 “I think there's too much chance for voter fraud. It's so close to the election, I think it would be very hard for them to get to count those properly,” Lynn Burney told us.
Another protester told us, "I want my vote to count and if we mail them in I don't think it will count."
AB4 will also set aside $3 million for the mail-in election in November. Donald Trump has been siding with Florida because he knows he'll win in a Red state unlike Nevada, a current blue state.

Other states plan on doing mail-in ballots as well.

(Source: KTVN - Channel 2 Reno)