Plan process stopped with system error on CBB Ultimate for Linux to S3 These are the relevant logs I can see, not too sure whether it is related to your problem or not. The only changed I made recently was to add some additional files to the plan but they don't appear to be the problem here.
2019-06-26 09:41:36,008940 [WARN ]: [ CBC ] [ 8 ] Cloud operation error (NoContent): No Content
2019-06-26 09:41:36,009211 [WARN ]: [ CBC ] [ 11 ] Finished with error, path: /CBB_domoticz/home/domoticz/domoticz/domoticz.db$/20190621020000/full.cbbitmap message: Operation error. Don't retry it
2019-06-26 09:41:36,009405 [INFO ]: [ CBB ] [ 4 ] Finished download file/part, path: /opt/local/CloudBerry Backup/etc/config/dfmap/{2c5f63cb-b78c-434e-b078-8b9a8b7576c9} position: 0 size: 0
2019-06-26 09:41:36,009499 [ERROR]: [ CBB ] [ 4 ] Error on download file/part path: /opt/local/CloudBerry Backup/etc/config/dfmap/{2c5f63cb-b78c-434e-b078-8b9a8b7576c9} code: 13 message: No Content
2019-06-26 09:41:36,009577 [WARN ]: [ CBB ] [ 4 ] Error on download dirrerential revision map, cloud path: /CBB_domoticz/home/domoticz/domoticz/domoticz.db$/20190621020000/full.cbbitmap error code: 13 mess$2019-06-26 09:41:36,010159 [WARN ]: [ CBB ] [ 4 ] Error on open last revision differential map, id: {2c5f63cb-b78c-434e-b078-8b9a8b7576c9} message: No such file or directory
2019-06-26 09:41:36,010260 [ERROR]: [ CBB ] [ 4 ] Backup error: /home/domoticz/domoticz/domoticz.db
message: Invalid last revision diffirential stream
code: 12
2019-06-26 09:41:36,010305 [ERROR]: [ CBB ] [ 4 ] Backup finished: /home/domoticz/domoticz/domoticz.db with errror: Invalid last revision diffirential stream
2019-06-26 09:41:36,183151 [WARN ]: QObject::startTimer: Timers cannot be started from another thread