1. You want to clean all data, just remove metamask then reinstall chrome extend again. Sometime do this step, can finish many problems.
2. use private china (private network). If you reconnect failed or miss connect,
3. private network best good action is
Sometime you sure private network is work and ok. But check netowrks list failed, this time just redo Custome Network then everything is ok.
4. How to know private network have web3 and ok?