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A busy signal or "no answer" usually means one of three things: the number is wrong or reaches a voice-only line, the receiving fax line is genuinely busy, or the machine is off or out of paper after hours. Before resending, call the number from your phone to hear what answers. Most failures clear up with a corrected number or a retry at a different time of day.
It means exactly what it means on a phone call: the line was in use when you called. Fax machines share lines more often than people realize. Many small offices run voice and fax on the same line: if someone is on a call, your fax gets a busy signal, and if someone picks up the ringing phone before the machine answers, your fax gets "no answer." Larger offices sometimes route several fax machines through one number, so a busy signal at 9 AM can simply mean three other people faxed that office at the same time. None of this indicates anything wrong with your document: it is a traffic problem, and retrying usually works.
| Error message | Likely cause | What to try |
|---|---|---|
| Busy, every time | Wrong number, or a line that is always in use | Call by voice; get a fresh number from the recipient |
| Busy, sometimes | Line genuinely occupied; shared voice/fax line | Retry mid-morning; avoid Monday 9 AM |
| No answer | Machine off, out of paper, or voicemail picked up | Call by voice; retry during business hours |
| Failed, zero pages sent | Voice-only line, disconnected number | Do not keep retrying; confirm the number first |
| Failed partway (e.g. 3 of 8 pages) | Call dropped on a noisy line | Resend the whole document; retry at a quieter hour |
Then the problem is the number, not the timing. Numbers that fail at 10 AM, 2 PM, and 7 PM are almost never working fax lines: they are voice-only lines, disconnected numbers, or fax numbers that were retired when the office switched providers. Get a fresh number directly from the recipient and have them read it back to you. One more possibility worth knowing: some offices set their machines to answer after several rings, and if their voicemail is set to fewer rings, the voicemail always wins. That one needs the recipient to fix on their end, so a quick call explaining what you hear when you dial it helps them sort it out.
The same rules apply: the most common reason any fax fails, including one sent through LetterAgent, is a bad destination number. Verify the number with the recipient before you send, and prefer a number you have successfully faxed before. When you send through LetterAgent, you describe the fax to your AI assistant, the page count is verified as part of the quote, you approve the exact total, and you pay once before it is sent, to US and Canadian numbers only. Fax is in private testing right now, so if a send ever behaves oddly, keep your confirmation details and ask your assistant to check the job's status.
Ready to fax it? Fax with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is sent.
LetterAgent is a working name. Prices include print, postage, and our service fee. US prices in USD, Canadian prices in CAD (Canadian prices exclude applicable sales tax, added at checkout). Currently in private testing.
Need help? Ask your assistant: it can check a job's status any time. If it ever can't handle something: hello@getletteragent.com