T42G Ringtone problem

[Relitech]

Hi,

We want to use a different ringtone for our Intercom (doorbell).
I've created a wavefile and I can upload it to the phone, but it will not be played at all.
It's in the list, but setting it as default (by the webbrowser) or selecting it on the phone, it will not be played.

I thought I used the right setting for the wavefile, 8K, 16 bit, mono and < 100K, but no go.

I've attached the wavefile.

Can anyone tell me what's wrong with this file or do I need another setting which allows me to use custom wave files?

Thanks and best regards,
Egbert