fax result.pdf

hey guys a customer asked me why is this OKI fax is giving these errors. I don't work on them so just helping him out- kind guy I am....
He sends jobs to these numbers everyday - sometimes it works - sometimes it doesn't? I have checked settings and country code and sent a test fax and report comes back excellent, so I can only assume the other fax is busy / out of order. Anyone have some official documentation on them. Thanks guys...I have att report if it helps