We have no way of saying where this error comes from for sure since it is returned by the system.
Usually this is an error related to source disk, however, in some cases, it might be the problem with the local destination.

Such an error almost never relates to the cloud storage. Most likely, it means that the files on the system are either corrupted or the hardware does not allow them to be processed. This is most likely what causes this speed issue.

Try applying the following changes

1) Decrease thread count to 2 in Tools > Options > Advanced.
2) Not run backup in high load hours (non working hours are recommended).
3) Please go to Tools - Options - Advanced and reduce Chunk size to 10MB.

Other general suggestions are:

- Check S.M.A.R.T. status of the physical drive that is backed up, for example, with this tool - http://hdtune.com/
- Check that drive's partition file system integrity by executing in elevated CMD:

chkdsk D: /f - where D: is replaced by the right drive letter

You might need to schedule check on next run if it cannot be performed immediately

Here is also the link that you might find helpful:
https://www.wikihow.com/Fix-a-Cyclic-Redundancy-Check-Error

After that problem is fixed please do the following:

1.Install the latest version of CloudBerry Backup

2. Please start Backup Service under administrator account: go to Tools > Change Service Account, enter local administrator account name and password, click OK. The service will be restarted automatically.
It is generally recommended to use local administrator's account name because domain administrator is not always a local admin on the host machine.

3. Run the backup operation again and check your backup speed.

My backups are running for more than 20 hours. Just making a backup of the changes. The plan does not include any additional directories. I must ensure that my backup strategy is set up to provide the quickest data backup possible. I still need to add more directories to the backup plan, but I can't keep the backup programme running constantly.

what version of the software are you running?