FaxFair guidesPublished November 2, 2026

Why is my fax not going through?

When your fax is not going through, the number may be busy, no fax machine may answer, or a person or voicemail may pick up. Other causes include a missing 1 or 9, a poor phone or internet line, a file that's too big, and a fax machine out of paper or memory.

Fax failed: what each error means and what to do

Error names and causes from the Brother, Canon and Epson manuals and help pages listed under Sources, read November 2, 2026. Other machines word them differently, so match yours by meaning.

Why a fax fails: the error or symptom, what it means and what to do
Error or symptom	What it means	What to do
Busy: No Response/Busy (Brother), #018 (Canon)	The other line was in use. Canon's #018 also covers a machine that didn't respond for other reasons, such as being switched off.	Check the number, as Brother suggests, and try again in a few minutes. Canon's advice for #018 is to ask the office to check their machine. Our guide to how long a fax takes covers automatic redials.
No answer or no fax tone: #005 (Canon), No Response/Busy (Brother)	The other machine didn't respond within 35 seconds. Canon names a machine that's switched off, or a busy line, as the causes.	Ask the office to check that their machine is on, then call the number from a phone. A steady high whistle means a fax machine answered, so send again (our guide to the fax machine sound explains the whistle). If a person or voicemail answers, see the next row.
Not a fax line: a person or voicemail answered	The number rings a phone or voicemail, so no fax machine answers. Canon's list has no code for this, and the FaxFair app says the number isn't a fax line.	Use the fax number on the form or letter that asked for the fax, not the office's phone number. Our guide to what a fax number is shows where to find it.
Wrong number format: a missing 1, country code or 9	The call never reaches the fax machine, so it fails like a busy or unanswered call. Some office phone systems also need a digit, such as 9, before an outside number.	The FCC says calls to Canada and most Caribbean nations take 1, the area code and the number, like a domestic long-distance call. From the US, other countries take 011 and the country code first. Brother's Dial Prefix setting can dial a 9 before every fax number, and Epson's WF-C878R uses a PBX line type and an access code.
Line or VoIP problem: Disconnected (Brother), or faxes fail to every number	Brother's Disconnected means the other side stopped the call. If that keeps happening, or faxes fail to every number, suspect your own line. Epson says it can't guarantee faxing over VoIP (phone service over the internet), since fax machines are designed for analog lines.	On VoIP, Brother suggests its Basic (for VoIP) setting. On DSL, Epson says to connect a DSL filter to the phone jack.
Communication error: Comm.Error (Brother)	Brother puts a communication error down to poor telephone line quality.	Brother says to send the fax again or connect the machine to another phone line. If the problem continues, Brother says to have your phone company check the line. After a communication error, Epson suggests the Slow(9,600bps) fax speed.
File too big or the wrong type: #003 (Canon), "The data being sent may be too large" (Epson)	Canon's #003 means the fax couldn't be sent because of its large data size. Online, a file type the service doesn't take stops the fax before it goes.	Canon says to lower the resolution and scan the document, and Epson suggests faxing the originals in batches. On faxfair.com, use PDF, JPG, PNG, WEBP or TIFF files, up to 10 files, 40 MB and 100 pages. Save iPhone HEIC photos as JPG first. If we can't prepare a file, the form says so before you pay.
Other machine out of paper: #012 (Canon)	Canon's #012 means the fax couldn't be sent because the recipient's machine ran out of paper.	Call the office and ask them to reload paper, then send the fax again.
Your machine's memory is full: #037 (Canon), Out of Memory (Brother)	The memory of the fax machine showing the message is full, so it can't hold the pages it's sending or receiving.	Canon says to wait for queued jobs to finish, print or delete received faxes stored in memory, and send a long document in sets. On some Brother models, Send Now sends the pages scanned so far.

Fax communication error: what Brother says causes it

Brother's help page for the MFC-8480DN and related models is dated 2011. It says the Comm.Error message can appear while a machine is sending or receiving a fax. Interference on the telephone line is the usual cause, in Brother's words "generally caused by interference on the telephone line". Other causes it lists are an incorrect telephone line connection and an alarm system or other device on the line.

If the fax machine's phone line runs through a surge protector or switching device, plug it straight into the wall jack and send again. If the fax then goes through, Brother says another device on the line was the cause. Our guide to how a fax machine works explains what the two machines say to each other during a call.

Fax not sending to one number only

If your faxes go through to other numbers but keep failing to one, look at the number first. Epson's manual says some fax machines reject incoming faxes without header information, so set up your machine's header. Some also reject anonymous calls, so if your line hides your caller ID, ask your phone company to unblock it. Then call the office to confirm the number and ask whether their machine is ready to receive.

When a FaxFair fax fails

In the FaxFair iPhone app, a fax can fail if the line is busy, no fax machine answers or the number isn't a fax line. The app says which, with a fix and a Try again or Change number key. A failed fax costs nothing, because the fax held for it goes back to your balance, and a free first fax that fails comes back too. FaxFair sends only to fax numbers in the US and Canada.

On faxfair.com, a private status page shows your fax's progress until it's delivered or fails. We only charge your card when the fax is delivered. If the fax fails, we cancel the payment and you aren't charged. You can send up to 5 website faxes a day to the same number, so if two tries fail, call the office before trying again.

If your own phone line keeps dropping faxes, send this one from the website instead. Upload your PDFs or photos and type the number, without an account or a phone line. As of November 2026, a fax of up to 40 pages costs $2.49, to any fax number in the US or Canada. For paper pages, the FaxFair iPhone app scans them with the camera.

Send a fax online

Questions

Why do I get a busy signal when I fax?

Because the other line was in use or didn't answer. Brother's No Response/Busy message covers both, and Canon's #018 covers a busy line or a machine that didn't respond for other reasons. Check the number and try again in a few minutes, and if it stays busy, call the office.

What does no answer mean on a fax?

It means no fax machine picked up. Canon's #005 means the other machine didn't respond within 35 seconds, and Canon names a switched-off machine or a busy line as the causes. Call the number from a phone. A steady high whistle means a fax machine, and a person or voicemail means it isn't a fax line.

Why does my fax keep failing?

If it fails to every number, look at your own line first. Try another phone line, a DSL filter or a VoIP setting, as Brother and Epson suggest. If it fails to one number only, confirm that number with the office and ask whether their machine is on and has paper.

Sources

The pages we read for this guide on November 2, 2026.