asterisk users - Oct 2005 - Planet Vip-150T

Hi All,
I'm having problem with this phone.
Problems are regarding voicemail message alert on the phone.
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handle_response: Host 'xxx.xxx.xxx.xxx' does not implement
'NOTIFY'
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Can somebody help?
On the phone manual, is written that it can acept MWI, but... not mine!!!

Thanks!
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.:FaberK:.