The device is FTD mode, registered successfully to FMC, and sent the configuration correctly. After one day or so, the device automatically offline, synchronization button can not restore the online. Check the connectivity and port between FTD and FMC, then delete the device on FMC, re-register, and register successfully, but after one day or so, the FTD device offline again. After the device was offline, FMC to FTD communications were checked, because the on-site client computer can manage FMC and take the MPLS dedicated line. error log as follow ATTACH What can I CHECK IT?