Client offline: we found UrBackupClient service is getting stopped frequently and as per the event viewer logs UrBackup service KERNELBASE.dll is not running properly

Sorry you are having issues. To solve the problem the client (debug) log and/or a crash dump would be useful.
If possible, could you post it or send it?

This post describes how to change the client to debug logging, where it is stored, where the crash dump is found and where to send it to if posting is not possible: Having problems with UrBackup? Please read before posting

Thanks!