Hi everyone

First a quick presentation, I am Pedro, from Porto, Portugal I have a 2003 Volvo XC70 D5 which I love.
Lately when I use the cruise control after a while it disconnects and does not allow you to use it again until I switch off and start over, any ideas on what might be? Even if I press the Cruise button the "Cruise" word does no appear in the screen until I switch the ignition off and on again.

Thanks,
Pedro