20 Most Recent AT&T 974 4Line Corded Phone - Page 7 Questions & Answers

Check this site: AT 1715 Installation And Operation Manual AT 1715 Installation And Operation Manual

That VM is not physically on your cell phone. You need to call your cell phone provider's voice messaging system and then listen to it.

If your Phone service is recording messages, that disconnects your line. You need to have them turn that feature off, OR set the answering machine to answer is less rings, say two or three. If the FAX machine listens to the line, it can still be set at a higher amount of rings, say four, and should still answer any FAX signal as it's sent to the answering machine.

Maybe in the manual:

http://cdn-media-att.vtp-media.com/media/p/document2/products/%7BC558AB9F-B1EA-4B9D-BA99-A45FE222FCC4%7D/TL7912_UM_6_Final.pdf

You are not properly connected to a live telephone line.

Check your phone wiring in the wall socket is ok