Backup failure in Virtualmin

I am getting the following error while backing up and not even getting an email on failure. all the email settings i have configure seems correct.

Copying Apache log files …
Failed to write to /home/cloud/.backup/cloud.xeeor.com_web_alog : Broken pipe at /usr/libexec/webmin/ line 1397, line 31438.

awaiting reply. Thanks

Anyways leave it problem is solved it was the Hard kilobyte limit and soft kilobyte limit in Webmin->system->Disk Quotas->Groups that needed to be increased for that particular server.