The phone rings at midnight

OK... wired connection with the box, it's really the base of the phone that manages the calls, not the box.

Try to mute the ringtone of the handset at least for one night... (long press on the * key)

Also check the blocking of hidden calls (at the bottom of page 15) they are not recorded by the log, unless I'm mistaken.

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Very difficult to catch a black cat in a dark room.
Especially when it's not there...

After searching a lot, I found on my device that it originated from the "energy-saving" feature. It indicated two different times, one at 00:00 and the other at 07:00, without me knowing what they corresponded to. When it switched from 00:00 to 07:00, it started ringing at 07:00 in the morning instead of midnight. So I disabled the energy saver and the problem is solved. It doesn't ring anymore.

Hello,
Could you describe to us, as precisely as possible, what is displayed on the handset screen or a photo of it?

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Very hard to catch a black cat in a dark room.
Especially when it’s not there...

Simple precision: The icon in the top left is not the wifi but a signal strength indicator for the radio connection with the base...

No alarm clock icon instead of the date.
The daily ringing at midnight... does make one think directly of an alarm clock.
Although apparently the alarm clock is not seen in service.
However, check that the alarm time is not exactly midnight... 00:00

Is this phone connected to an Orange Livebox with a cable?

You said no number displayed.
Have you checked the call log to see if among the numbers listed there is one around midnight? See manual on page 10.
I invite you to clear the call log before going to bed and see if there are any numbers stored the next morning.

Also check that the handset is properly placed on its base. Unless I'm mistaken, there is a sound when placing the handset on the base or charger.
If misaligned, it could emit this sound due to vibrations.

The manual: https://gse.gigaset.com/fileadmin/gigaset/images/CustomerCare/Manuals/A4x/AS470A/A31008-M2501-N101-2-7719_ba.pdf

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Very difficult to catch a black cat in a dark room.
Especially when it's not there...

The phone is connected to the box via a cable. I checked the inputs. And the wake-up time is not 12 o'clock. When I check it, it blinks at 9 o'clock. But it's not activated. The handset is also placed correctly.
Thanks for the info on the icon. Radio link intensity with the base is excellent :).
I don't have any calls in the log either.
Anyway, it’s a puzzle.
Have a good evening.

Hello,

Unplug the phone at night and test with another phone.

I unfortunately no longer have another phone. For your information, I went on vacation and had my landline forwarded to my mobile. But the phone at home was disconnected. I never found any missed calls in the morning????. I will try to enable call forwarding tonight to see if I have a call... Thank you for your advice.

I will try to turn off the ringer tonight. I didn't get a notification of your response, that's why I'm only replying now. Last night, I sent something to my phone and didn't receive any call notifications, nothing. Did it ring???

Hello. I picked up my phone with the message that no malfunction was noted!!! We haven't heard any ringing since Friday. I will therefore mark it as resolved but we will never know the end of the story... Thank you and have a good week.