If for whatever reason the following doesn't fix your issue, join the Discord server and ask in the public channels only for help. Do not respond to any DMs as scammers might try to trick you into giving them your funds!
Download the NIX Blockchain Bootstrap file.
Close/shutdown your wallet.
Navigate to the NIX data directory.
Delete blocks and chainstate directories.
Unzip contents of the bootstrap .zip file to the NIX data directory.
Restart your wallet.
First, stop the wallet and delete the blocks and chainstate directories. Though not necessarily required, you might also want to delete the peers and banlist files.
nix-cli stoprm -r ~/.nix/{blocks,chainstate,peers.dat,banlist.dat}
NOTE: If you used Crypto Sharks' script to install, use "systemctl stop NIX" instead of "nix-cli stop"
You can use wget or gdown to download the file..
wget --load-cookies /tmp/cookies.txt "https://docs.google.com/uc?export=download&confirm=$(wget --quiet --save-cookies /tmp/cookies.txt --keep-session-cookies --no-check-certificate 'https://docs.google.com/uc?export=download&id=1iDVeHO5hSeSENVwj8GAHI-YbNMYjMPqD' -O- | sed -rn 's/.*confirm=([0-9A-Za-z_]+).*/\1\n/p')&id=1iDVeHO5hSeSENVwj8GAHI-YbNMYjMPqD" -O NIXBlockchain-621214.zip && rm -rf /tmp/cookies.txtunzip NIXBlockchain-621214.zip -d ~/.nix
If your system does not have wget and unzip already installed (commands assume Ubuntu Linux):
sudo apt updatesudo apt install wgetsudo apt install unzip
gdown https://drive.google.com/file/d/1iDVeHO5hSeSENVwj8GAHI-YbNMYjMPqDunzip NIXBlockchain-621214.zip -d ~/.nix
If your system does not have python-pip, gdown, and unzip already installed (commands assume Ubuntu Linux):
sudo apt updatesudo apt install python-pipsudo -H pip install gdownsudo apt install unzip
​
Restart your wallet.
nixd &
NOTE: If you used Crypto Sharks' script to install, use "systemctl start NIX" instead of "nixd &"