Why your fax failed, and what to do about each cause
Most failures are the far end, not your document — a line that rings out, a machine out of paper, a number that became a voice line. Here is how to tell which one you hit.
A fax fails loudly compared with an email, which is one of its few remaining advantages. The failure comes back with a cause, and the cause tells you whether to retry, fix something at your end, or pick up the phone. What follows is every cause worth knowing, roughly in order of how often it happens.
No answer
The line rang and nothing picked up. Almost always the far end: a machine switched off overnight, or a number that is only staffed during office hours. This is the most common failure and the least alarming.
What to do: nothing. A fax service retries this automatically, spaced out over the next while. Retrying by hand immediately just adds a second failed attempt to the record.
Busy
Something answered, and it was a fax machine already mid-call. Common at organisations that receive a lot of faxes on one line, and at exactly the times you would expect — first thing, and just after lunch.
A voice answered
The call connected to a person or a voicemail greeting rather than a fax tone. This is the cause worth stopping for, because retrying will not fix it and it usually means one of three things: the number is a voice line, the number was reassigned, or somebody has to switch the machine into fax mode manually — which is still the arrangement in a surprising number of small offices.
What to do: phone the number and ask. If it is a shared line, ask them to start their machine before you resend.
The transmission started and stopped
The worst one, because it half-worked. The report will show fewer pages accepted than you sent, and the recipient has those pages printed. Poor line quality is the usual reason, and long documents are the usual victims — every extra page is another minute for the line to fail in.
Resend the whole thing
Never resend just the missing pages. The recipient has no way of knowing your second fax continues the first, and a document reassembled from two faxes by somebody who is guessing is worse than a document sent twice.
The far end is out of paper or memory
A machine that cannot store or print what it is being offered refuses the call. It looks like a busy signal or a hard rejection depending on the machine. Nothing on your side will change it, and it usually clears the next working day.
The number was wrong
Not a failure so much as a success at the wrong address. The two shapes: a missing country code — a fax number needs its full international form, the same as a phone number — and a transposed digit, which produces a perfectly clean transmission report from a stranger's machine. If the report says success and the recipient says nothing arrived, check the number on the report first.
The document was too large
The one failure that is genuinely yours. Every plan caps the pages in a single fax — the limit exists because an hour-long call is an hour in which a line can drop, not to be mean. A 60-page contract will not go out under a 50-page cap. Split it at a sensible boundary and tell the recipient there are two, or move up a plan.
The scan was the problem
Not a failure, but worth listing here because it produces the same phone call. A page that arrives black, streaked or unreadable usually left as a photograph of a document rather than a scan of one. What a fax does to a PDF covers what survives the trip and what does not.
When to stop retrying
Three failures with the same cause is not bad luck, it is a fact about that number. At that point the fastest route is a phone call — and if it turns out the number has not been a fax line for two years, that is worth knowing before the fourth attempt.