Hello & Welcome to Just Answer,
I'm Greg and will do my best to assist you today.
Sorry to hear of any issue you are having with your phones.
To help you with this issue, may I ask:
1) The FULL Model Number of the phone system you are working with? If this is a cordless system, that model should be printed on a sticker on the bottom or back of the MAIN base and START with KX-TG, but have NO "A" in it (that is for the cordless handsets or chargers).
2) WHEN did you start to see this message on the screen(s) of your handsets?
3) What phone service provider (phone company) you have for this phone line?
Please REPLY using the box below.
I see it has been a few days and I just wanted to follow up to see if you have any more questions concerning this issue or if the issue was resolved?
I look forward to any further questions or results that you may have.
Thanks, ***** *****--. .-(im)