JAVA - Save Configuration not working

Hi Team

icontrol version:13.0.0
Device Version: 11.x

we are trying to save the configuration of F5 device using the following code in java.

Interfaces interface = new iControl.Interfaces(ipAddress, userName, decryptedPassword);boxInterface.getSystemConfigSync().save_configuration("backup.ucs", iControl.SystemConfigSyncSaveMode.SAVE_FULL);

we are getting exception as follows while saving the configuration,

Exception caught in System::urn:iControl:System/ConfigSync::save_configuration() Exception: Common::OperationFailed primary_error_code : 16908289 (0x01020001) secondary_error_code : 0 error_string : Error saving configuration

we checked that the device have sufficient space also, what may be root cause of this issue, is there any alternate way to save configuration?