If you see the above protocol stack error message in the log file, it means Klaytn failed to start because the full path name of current working directory is too long. Please launch a Klaytn node with a shorter full data directory. The maximum allowed length of path name depends on operating system.
EN can't connect to CC with following log message.
It could happen when genesis of mainchain and service chain differ. Please check genesis of both chain are same.
Head state missing error
"ERROR[06/21,14:35:16 +09]  Head state missing, repairing chain number=2955620 hash=66bba2…e15f8d
Fatal: Error starting protocol stack: rewound to block number 0, but repair failed"
Answer Due to a compatibility issue, we strongly recommend to upgrade EN's binary to v0.9.6 if you have been running an EN with older versions (<= v0.8.2). If it is your first time upgrading the EN to v0.9.x and want to migrate the data from the older version, you must specify the option ADDITIONAL="--db.num-statetrie-partitions 1" in the configuration file when you install the newer version.