If you have an standard phone, connect it to the line and try to make calls. I miswired phone line can cause the problem you are having. If the line tests ok, try changing the fax communication settings, turn off error correction mode and pick a slower communication speed.
If you find the information provided useful or solves your problems, help other users find the solution easier by giving kudos and marking my post as an accepted solution. I am a volunteer, offering my knowledge to support fellow users, I do not work for HP nor speak for HP.
Be alert for scammers posting fake support phone numbers and/or email addresses on the community. If you think you have received a fake HP Support message, please report it to us by clicking on "Flag Post".