There was a long fork chain by clients on 3.0.1 or older. Both chains had slow block generation. The proper chain appears to have caught up and is now seeing rapid block generation. Please upgrade to 5.0.1 and mint to help reduce the issue.
SjHMF9zuPcMMMJd3uFGfMnGWEJt5gLPvQ7 was the primary minter on the fork chain. If that happens to be you, upgrade as soon as possible. Don't make any transactions using 3.0.1 or older to avoid losing funds.
Linux 5.0.1: https://bitbucket.org/JordanLeePeershares/nubit/downloads/nu-5.0.1-linux-gitian.zip
Windows 5.0.1: https://bitbucket.org/JordanLeePeershares/nubit/downloads/nu-5.0.1-win-gitian.zip
macOS 5.0.1: https://github.com/jooize/Nu-macOS/releases/download/v5.0.1/Nu-5.0.1.dmg
Your client may fail to continue with your current blockchain database, meaning you need to remove blk0001.dat and blkindex.dat from the wallet directory and redownload the blockchain.
- Windows: %APPDATA%\Bitcoin
- macOS: ~/Library/Application Support/Nu
- Linux: ~/.nu