Fax Troubleshooting Checklist

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SummaryWhat should I do when I encounter general fax failures?
General fax failures are caused by various reasons.  The following are the most common things you need to consider to avoid sending or receiving fax errors.

Causes of Fax Failures


Causes of Fax Failures

Below are the tips on checking the causes of fax failures.  It is important to follow the guidelines to avoid these errors:

Email to Fax

• When trying to send faxes through email, make sure that you Add a Trusted Email Address to Send Faxes.  You can only send faxes from your trusted addresses.
The file size of the document should be less than 20 MB.
Send the fax using this format <faxnumber>@rcfax.com.​
• Corrupt File -
The document may be corrupt.  Try sending another file or make a text document in Notepad, save it, and then attach the test file.  
Unsupported File Type - Make sure that the file type is a supported file attachments for faxes
File Size Too Large - The attachment may have exceeded the 20MB limit.  Try sending a smaller file size.

NOTE:  This size limitation is for all fax docs, through print to fax, desktop app and fax through email.

• Ampersand characters - The filename of your fax attachments should not include ampersands (e.g. &) or other special characters for you to able to send it.

Internet Connection

Make sure that your device is connected to the Internet.  RingCentral uses the Internet to send data.
Make sure that the firewall is on both the sender and the receiver's end are configured to send/receive faxes.
Make sure that you have calling credits on your account.

File Attachment

Make sure that the attached document is not corrupt.  If unable to send the fax, try attaching another file and then send.
Ensure that the document is a supported file attachments for faxes.
• When documents go beyond the printable area, it may be best to resize them using your PDF viewer at around 90-95%.
The filename of your fax attachments should not include ampersands or other special characters.

NOTE: This also resolves the error: "The Information could not be saved. Please try again later"

Using Print to Fax

• Application Issue - Sometimes an application issue can cause a file attachment issue.  Below are the steps to attach the file using the RingCentral Internet Fax Printer option.

IMPORTANT:  Make sure that you have the RingCentral Desktop App is installed on your computer.

Step 1:

Open the document in its original application (ie. Microsoft Word)

Step 2: 

Go to File menu and click Print.  

Step 3:

Choose RingCentral Internet Fax Printer menu and then click Print.  The document should be added to the fax.

Step 4:

Select a contact you want to send the file. 

Step 5:

Click Send.

NOTE:  If issues persist, try using a different program and file type (i.e. Adobe Acrobat with a PDF file)

desktop app issue

If you are unable to attach any file type from multiple applications, the desktop app might be causing the problem.  Try uninstalling and reinstalling the desktop app.

Partially Received faxes

Partially received faxes are fax documents that only show a few pages of the faxed document.  It can occur when the fax transmission is interrupted.  Causes of partially received faxes include poor line quality and/or errors from the sending or receiving fax machine.

RingCentral's fax services will save and deliver all of the pages that were successful, and mark the fax as partially received.  Typically, the sending machine will automatically resend the fax if it detects that the transmission was not successful.  Depending on the fax machine, this may take anywhere from one (1) to 10 minutes.

Using Traditional Fax Machine

It is possible to use traditional fax machines with RingCentral internet fax service.  Here are some guidelines to ensure the best possible connection with our service:

Dedicated Phone Line for Fax

Avoid using DSL phone filters and phone splitters. Either item may interfere with the ability of the fax machine to answer or receive a fax.
Use a dedicated fax phone line to ensure that the receiving fax machine is always available.  Do not share this line with additional phones.  Some answering machines and caller ID devices can cause disruptions.  The less equipment attached to a line, the better.

T38 Protocol

T38 is a FAX over IP protocol that describes how to send fax over a data network.  This is needed because fax data cannot be sent over a computer data network in the same way as voice.
If you want to use traditional fax machine with your VoIP phone. Use a VoIP gateway and an ATA (Analog Telephony Adapter) that supports T38 protocol that is designed to allow fax to travel over a VoIP network.
Use a short phone cord to minimize the chance of signal loss.

Fax Machine Advanced Settings

Most fax machines have an “overseas” mode that may help resolve partially received faxes.  It will lower the baud rate of the fax machine and turn off Error Correction Mode (ECM).  If there is no overseas mode, adjust the BAUD rate to 9600 or slower, and turn off the ECM to get the same results.

Fax Machine Troubleshooting

• Ask the other party to set their fax machine to Overseas mode.  It will lower the Baud rate and turn OFF the Error Correction Mode(ECM).  If there is no Overseas mode, have them adjust the BAUD rate to 9600 or slower, and turn off the ECM to get the same results.  These settings can be found on the fax machine's R/W parameters or Advanced Fax settings.  For specific instructions, refer to the fax machine’s manual or support.

• Fax machines would work best with a direct landline phone connection, not a VoIP broadband connection.  VoIP connections are optimized for voice, not data or fax transmissions.

• Fax machines may require a specific modem type.  Ensure that the modem attached to the fax machine is a fax modem.  Refer to the device’s documentation for more information.

IMPORTANT:  If you're still getting partially received faxes after adjusting the BAUD rate and turning OFF the Error Correction Mode.  It is possible that your fax machine is not compatible with RingCentral Fax Service.

RingCentral Account Troubleshooting

• If the fax machine is not able to hear fax-tones when dialing into a RingCentral number set to receive voice and fax, you can Set Additional Numbers to Fax Only.

• Alternatively, you can simply add a direct number under the user with the number type set to Fax Only then send this number to your contacts as your fax number.

• If you’re receiving partial faxes, try to free up mailbox space by deleting old or unused faxes in your account.  Having full mailbox is also one of the causes of partially received faxes.

• If you do not receive any additional attempts after a partial fax is received, ask the sender to resend the fax.

IMPORTANT:  When sending file documents for faxes, make sure that the file attachment is supported for faxes


See also:

Connecting the ATA and Fax Machine to Your RingCentral Online Account
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