Read messages on Gigaset AS 405 cordless phone

No need to use capital letters...
They are considered aggressive online and make it seem like you are shouting...

So AS405A...

When a caller tries to reach you in your absence, there are two possibilities:
- If they don't leave a voicemail, the left screen button on the handset flashes, and the screen displays New messages.
To find out who called, you need to check the call log (see the manual on page 9)
- If they leave a voicemail.
If the answering machine is properly set up and working, the light on the base changes from solid (on) to flashing (there is one or more messages)
To check the message(s), see the manual on page 10.

For your answering machine to be able to record messages, it must activate before your operator's voicemail.
Operators usually set their voicemail activation to 5 rings (about 20 seconds) by default.
Your answering machine should therefore be set to a lower value... 18 seconds is the adjustment to adopt (or you need to set it with your operator via customer service)
For the adjustment, see the manual on page 21
Excerpt(click on the image to open it enlarged in a new tab)
--

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

Passing by, I am... and your response allowed the resolution of my problem.
Thank you, Baladur.