How long does it generally take for the sent fax status to change from Sending to Sent to Delivered or Not Delivered?

The fax status on sent fax record takes a little longer to update in Salesforce rather than the time the fax is actually sent/delivered. The reason it takes longer for status to update is because of the multiple platforms the fax travels through, from Salesforce to eFax platform to fax recipient telco service and then back to eFax and then to Salesforce for record to be updated. However, the fax itself is usually delivered within 2-5 minutes of being sent from your Salesforce if no other fax variables causing delay.

To summarize general estimate of time to update though different fax status’:
When you first send the fax record, it will show Status of “Sending.” The fax should then be sent to the recipient’s fax number within 2-5 minutes minutes (may take longer if very large fax file with multiple pages or if recipient fax line busy, etc) and then the status will be updated to “Sent” within 2-4 minutes after fax is originally sent. Once eFax system receives confirmation that the fax was received by recipient, then the status will be updated to “delivered” which could take roughly 10-15 minutes (sometimes longer depending on what is in the fax and time of day with high fax volume across platform) for status to update on sent fax record from when it was originally sent from your Salesforce. If the fax status changes to “Not Delivered” there will also be a value populated in the “detailed fax status” field on sent fax record so you can better understand why the fax was not successful. Also “number of retries” can be a helpful field to have visible on layout.